39.1 Atopic Dermatitis, Contact Dermatitis & Eczematous Flares

ABFM Family Medicine Certification Study Guide Exam

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1 Chapter 1: Exam Structure, Blueprint & Clinical Decision-Making

1.1 Exam Blueprint, FMCLA vs. One-Day Exam & Board Scoring 1.2 Clinical Reasoning, Test-Taking Strategy & Ambiguity Management 1.3 Evidence-Based Medicine & Clinical Practice Guidelines in Primary Care

2 Chapter 2: Healthcare Systems, Practice Management & Quality

2.1 Practice Management, Billing, Coding & Documentation 2.2 Quality Improvement, Patient Safety & Diagnostic Stewardship 2.3 Interprofessional Team-Based Care & Care Coordination

3 Chapter 3: Ethics, Law, Biostatistics & Health Equity

3.1 Medical Ethics, Informed Consent & Surrogate Decision-Making 3.2 Biostatistics, Clinical Epidemiology & Diagnostic Test Interpretation 3.3 Social Determinants of Health, Health Equity & Cultural Humility 3.4 Physician Wellness, Burnout Prevention & Professionalism

4 Chapter 4: Lifestyle Counseling & Behavior Change

4.1 Alcohol Use Screening & Brief Intervention 4.2 Illicit Drug & Cannabis Counseling 4.3 Tobacco & Vaping Cessation Counseling

5 Chapter 5: Nutrition, Physical Activity & Chronic Disease Prevention

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6 Chapter 6: Routine Adult Immunizations

6.1 ACIP Adult Respiratory Vaccines: Influenza, COVID-19, RSV & Pneumococcal 6.2 ACIP Adult Non-Respiratory Vaccines: Tdap, Shingrix, HPV & Hep B 6.3 Immunizations in Special Populations: Pregnancy, Asplenia & Immunocompromise

7 Chapter 7: Pediatric Health Maintenance & Surveillance

7.1 Newborn Examination & Early Postnatal Care 7.2 Well-Child Care, Developmental Surveillance & Milestones 7.3 Pediatric & Adolescent Screening: Vision, Hearing, Anemia & Lead 7.4 Pediatric Oral Health, Dental Screening & Fluoride

8 Chapter 8: Behavioral Health & Safety Screening

8.1 Primary Care Depression, Anxiety & Behavioral Health Screening 8.2 Domestic Violence, Intimate Partner Violence & Firearm Safety 8.3 Occupational Health & Recreational Safety Counseling

9 Chapter 9: Adult Preventive Screening: Cardiovascular & Metabolic

9.1 Cardiovascular Disease & Hypertension Screening 9.2 Type 2 Diabetes Screening & Prediabetes Risk Stratification 9.3 Abdominal Aortic Aneurysm & Osteoporosis Screening

10 Chapter 10: Adult Cancer Screening: Breast & Gynecologic

10.1 Breast Cancer Screening & Risk-Assessment 10.2 Cervical Cancer Screening & ASCCP Algorithms 10.3 Skin Cancer Clinical Assessment & Counseling

11 Chapter 11: Adult Cancer Screening: Colorectal, Lung & Prostate

11.1 Colorectal Cancer Screening Modalities & Intervals 11.2 Lung Cancer Screening with Low-Dose CT 11.3 Prostate Cancer Screening & Shared Decision-Making

12 Chapter 12: Sexual Health, Infectious Disease Screening & Contraception

12.1 Sexual Health Counseling & Risk-Reduction Strategies 12.2 STI Screening: Chlamydia, Gonorrhea, Syphilis & Trichomoniasis 12.3 Bloodborne Infectious Disease Screening: HIV & Hepatitis C

13 Chapter 13: Reproductive Life Planning, Lactation & Preoperative Care

13.1 Preconception Planning & Comprehensive Contraception Management 13.2 Lactation Support & Breastfeeding Counseling 13.3 Preoperative Medical Evaluation & Pre-Participation Sports Exam

14 Chapter 14: Emergent Cardiovascular Conditions

14.1 Acute Coronary Syndromes & Myocardial Infarction 14.2 Acute Chest Pain Risk Stratification & Triage 14.3 Acute or Critical Valvular Heart Emergencies

15 Chapter 15: Cardiac Arrhythmias, Heart Failure & Hypertensive Crises

15.1 Acute Atrial & Ventricular Arrhythmias 15.2 Acute Decompensated Heart Failure & Cardiogenic Shock 15.3 Hypertensive Emergency & Urgency Management

16 Chapter 16: Vascular & Thromboembolic Emergencies

16.1 Pulmonary Embolism & Deep Vein Thrombosis 16.2 Acute Aortic Syndromes & Peripheral Vascular Emergencies 16.3 Critical Limb Ischemia & Acute Arterial Occlusion

17 Chapter 17: Neurologic Emergencies: Stroke & Altered Consciousness

17.1 Acute Ischemic Stroke & Intracranial Hemorrhage 17.2 Syncope Evaluation & Status Epilepticus 17.3 Acute Delirium, Encephalopathy & Severe Confusion

18 Chapter 18: Neurologic Trauma & Acute Cranial Emergencies

18.1 Concussion, Moderate-to-Severe TBI & Intracranial Injury 18.2 Thunderclap & Acute Severe Secondary Headaches 18.3 Acute Ophthalmologic Emergencies

19 Chapter 19: Acute Abdominal, Pelvic & Gastrointestinal Emergencies

19.1 Acute Abdominal & Pelvic Pain Triage 19.2 Upper & Lower Gastrointestinal Bleeding 19.3 Acute Hepatic Failure, Cholangitis & Severe Jaundice

20 Chapter 20: Acute Pulmonary & Airway Emergencies

20.1 Acute Hypoxic Respiratory Failure & ARDS 20.2 Severe Community-Acquired Pneumonia & Empyema 20.3 Acute Severe Epistaxis & Airway Obstruction

21 Chapter 21: Acute Traumatic Injuries & Wound Care

21.1 Major Trauma Resuscitation & Initial Assessment 21.2 Burn Assessment, Inhalation Injury & Resuscitation 21.3 Laceration Management, Complex Wounds & Animal Bites

22 Chapter 22: Acute Orthopedic & Musculoskeletal Emergencies

22.1 Acute Ambulatory Fractures & Initial Splinting 22.2 Compartment Syndrome & Major Orthopedic Trauma 22.3 Septic Arthritis & Acute Microcrystalline Crises

23 Chapter 23: Severe Infections, Sepsis & Systemic Emergencies

23.1 Sepsis, Septic Shock & Initial Fluid Resuscitation 23.2 Necrotizing Soft Tissue Infections & Severe CNS Infections 23.3 Anaphylaxis Diagnosis, Epinephrine Dosing & Airway Protection

24 Chapter 24: Metabolic, Endocrine & Electrolyte Emergencies

24.1 Diabetic Ketoacidosis & Hyperosmolar Hyperglycemic State 24.2 Critical Electrolyte Emergencies: Dyskalemias & Dysnatremias 24.3 Severe Calcium Abnormalities & Acute Adrenal Crisis

25 Chapter 25: Hematologic, Urologic & Dental Emergencies

25.1 Severe Symptomatic Anemias & Coagulopathic Emergencies 25.2 Testicular Torsion, Priapism & Acute Urinary Retention 25.3 Urgent Odontogenic Infections & Dental Trauma

26 Chapter 26: Psychiatric, Behavioral & Obstetric/Gynecologic Emergencies

26.1 Suicidal Ideation, Acute Agitation & Behavioral Emergencies 26.2 Acute Physical & Sexual Assault Care 26.3 Life-Threatening Vaginal Bleeding & Ectopic Pregnancy 26.4 Environmental Heat Stroke & Severe Hypothermia

27 Chapter 27: Acute Head, Neck & Neurologic Symptoms

27.1 Primary Acute Headaches: Migraine, Tension & Cluster 27.2 Concussion & Minor Closed Head Injury Evaluation 27.3 Transient Ischemic Attack Evaluation & ABCD2 Risk Scoring

28 Chapter 28: Acute Cranial Nerves, Hearing & Sensory Symptoms

28.1 Peripheral Neuropathies: Bell's Palsy, Carpal Tunnel & Radiculopathy 28.2 Acute Tinnitus, Sudden Sensorineural Hearing Loss & Cerumen Impaction 28.3 Acute Dizziness, Benign Paroxysmal Positional Vertigo & Vestibular Neuritis

29 Chapter 29: Acute Upper Respiratory Tract Infections

29.1 Acute Viral Rhinosinusitis vs. Bacterial Rhinosinusitis 29.2 Acute Pharyngitis: Group A Streptococcus & Centor Criteria 29.3 Acute Otitis Media, Otitis Externa & Serous Effusion

30 Chapter 30: Acute Lower Respiratory Infections & Cough

30.1 Influenza, COVID-19 & Viral Respiratory Syndromes 30.2 Acute Bronchitis & Lower Respiratory Tract Infections 30.3 Ambulatory Community-Acquired Pneumonia

31 Chapter 31: Allergic, Nasal & Non-Infectious Pulmonary Conditions

31.1 Allergic Rhinitis & Acute Non-Anaphylactic Allergic Reactions 31.2 Acute Dyspnea in Ambulatory Care 31.3 Interstitial Lung Diseases & Sarcoidosis Presentation

32 Chapter 32: Acute Chest, Cardiac & Vascular Symptoms

32.1 Palpitations Evaluation & Arrhythmia Triage in Primary Care 32.2 Deep Vein Thrombosis & Superficial Thrombophlebitis 32.3 Ambulatory Hypotension & Orthostasis Evaluation

33 Chapter 33: Acute Upper Gastrointestinal Conditions

33.1 Peptic Ulcer Disease & Gastritis 33.2 Dysphagia, Esophagitis & Acute Esophageal Disorders 33.3 Acute Nausea, Vomiting & Foodborne Illness

34 Chapter 34: Acute Lower Gastrointestinal Conditions

34.1 Acute Infectious Diarrhea & Gastroenteritis 34.2 Acute Constipation & Functional Bowel Changes 34.3 Ano-Rectal Disorders: Hemorrhoids, Fissures, Abscesses & Pruritus Ani

35 Chapter 35: Inflammatory, Functional & Malabsorptive GI Disorders

35.1 Acute Flares of Inflammatory Bowel Disease 35.2 Irritable Bowel Syndrome: Diagnosis, Subtyping & Management 35.3 Celiac Disease & Malabsorption Syndromes

36 Chapter 36: Acute Abdominal, Hepatic & Biliary Disorders

36.1 Ambulatory Abdominal & Pelvic Pain Triage 36.2 Acute Cholecystitis, Biliary Colic & Pancreatitis 36.3 Acute Liver Injury & Viral Hepatitis

37 Chapter 37: Acute Abdominal Wall, Hernias & Dental Conditions

37.1 Abdominal Wall, Inguinal & Ventral Hernias 37.2 Acute Dental Pain, Odontogenic Abscess & Aphthous Ulcers 37.3 Acute Edema: Unilateral vs. Bilateral Diagnostic Evaluation

38 Chapter 38: Acute Infectious Dermatoses

38.1 Bacterial Skin Infections: Impetigo, Cellulitis & Cutaneous Abscesses 38.2 Fungal Skin Infections: Tinea Corporis, Cruris, Pedis & Onychomycosis 38.3 Viral Cutaneous Infections: Herpes Simplex, Zoster & Molluscum Contagiosum

39 Chapter 39: Inflammatory, Allergic & Autoimmune Dermatoses

39.1 Atopic Dermatitis, Contact Dermatitis & Eczematous Flares 39.2 Non-Infectious Rashes: Urticaria, Drug Eruptions & Erythema Multiforme 39.3 Cutaneous Malignancies & Premalignant Lesions: AK, BCC, SCC & Melanoma

40 Chapter 40: Acute Shoulder, Elbow & Upper Extremity Injuries

40.1 Rotator Cuff Pathology, Tendinopathy & Shoulder Impingement 40.2 Lateral & Medial Epicondylitis, Olecranon Bursitis & Elbow Sprains 40.3 Wrist & Hand Soft-Tissue Injuries: De Quervain, TFCC & Finger Sprains

41 Chapter 41: Acute Knee, Ankle & Lower Extremity Injuries

41.1 Meniscal Tears, Ligamentous Knee Injuries & Patellofemoral Pain 41.2 Ankle Sprains, Ottawa Ankle Rules & Achilles Tendinopathy 41.3 Plantar Fasciitis, Shin Splints & Overuse Syndromes

42 Chapter 42: Acute Ambulatory Fractures & Dislocations

42.1 Distal Radius, Scaphoid & Common Upper Extremity Fractures 42.2 Metatarsal, Clavicle & Common Lower Extremity Fractures 42.3 Joint Dislocation Management: Nursemaid's Elbow & Shoulder Subluxation

43 Chapter 43: Acute Axial Musculoskeletal Pain & Falls

43.1 Acute Low Back Pain: Red Flags, Strain & Disc Herniation 43.2 Acute Cervical Strain, Whiplash & Axial Neck Pain 43.3 Evaluation of Falls in Ambulatory & Older Patients

44 Chapter 44: Acute Inflammatory Arthropathies & Generalized Pain

44.1 Acute Inflammatory Arthritis & Spondyloarthropathies 44.2 Myalgias, Rhabdomyolysis & Post-Viral Pain Syndromes 44.3 Acute Non-Headache Pain Management Strategies

45 Chapter 45: Acute Renal, Urinary & Genitourinary Conditions

45.1 Uncomplicated UTI, Pyelonephritis & Acute Urethritis 45.2 Hematuria Workup & Glomerulonephritis 45.3 Nephrolithiasis & Acute Urinary Tract Obstruction

46 Chapter 46: Acute Male Genitourinary & Prostatic Conditions

46.1 Acute Prostatitis, Epididymitis & Orchitis 46.2 Acute Scrotal Pain: Torsion vs Appendage, BPH & Male Genital Emergencies 46.3 Acute Urinary Retention & Incontinence Evaluation

47 Chapter 47: Acute Women's Health & Early Pregnancy Care

47.1 Early Pregnancy Diagnosis, Dating & Initial Complications 47.2 Abnormal Uterine Bleeding & Acute Menstrual Disorders 47.3 Premenstrual Syndrome & Premenstrual Dysphoric Disorder

48 Chapter 48: Breast Disorders, STIs & Pediatric Elimination

48.1 Palpable Breast Mass, Mastitis & Nipple Discharge 48.2 Sexually Transmitted Infections: Diagnosis, Staging & CDC Guidelines 48.3 Pediatric Enuresis & Encopresis

49 Chapter 49: Systemic Signs, Metabolic Dysregulation & Miscellaneous Infections

49.1 Acute Fever, Sepsis Screening & FUO in Primary Care 49.2 Acute Hyperglycemia & Symptomatic Hypoglycemia 49.3 Electrolyte Abnormalities: Mild-to-Moderate Disturbances 49.4 Vector-Borne, Tick-Borne & Rickettsial Illnesses

50 Chapter 50: Chronic Cardiovascular Diseases: Hypertension & Ischemia

50.1 Essential Hypertension Management: 2025 AHA/ACC Guideline & JNC Strategies 50.2 Chronic Coronary Artery Disease & Post-MI Secondary Prevention 50.3 Chronic Heart Failure: HFrEF, HFpEF & Quadruple GDMT

51 Chapter 51: Chronic Vascular, Valvular & Dyslipidemic Diseases

51.1 Peripheral Arterial Disease & Claudication 51.2 Chronic Valvular Heart Disease & Murmur Evaluation 51.3 Lipid Disorders & ASCVD Risk-Based Statin Therapy

52 Chapter 52: Chronic Respiratory Diseases: Asthma & COPD

52.1 Chronic Asthma Management: GINA Stepwise SMART Therapy 52.2 Chronic Obstructive Pulmonary Disease: GOLD Recommendations 52.3 Solitary Pulmonary Nodule Evaluation & Fleischner Society Criteria

53 Chapter 53: Chronic Metabolic Diseases: Diabetes Mellitus

53.1 Type 2 Diabetes Management: ADA Pharmacotherapy Algorithms 53.2 Type 1 Diabetes: Basal-Bolus Insulin, CGMs & Diabetic Complications 53.3 Diabetic Microvascular & Macrovascular Disease Surveillance

54 Chapter 54: Obesity, Nutrition & Metabolic Bone Diseases

54.1 Medical & Behavioral Management of Obesity & Incretin Mimetics 54.2 Osteoporosis & Metabolic Bone Disease: DEXA, FRAX & Antiresorptives 54.3 Nutritional Deficiencies: Vitamin D, B12, Iron & Malnutrition

55 Chapter 55: Chronic Endocrine Disorders

55.1 Primary & Subclinical Hypothyroidism, Hyperthyroidism & Nodules 55.2 Adrenal Disorders: Addison's Disease & Cushing's Syndrome 55.3 Hypercalcemia, Hyperparathyroidism & Pituitary Disorders

56 Chapter 56: Chronic Kidney Disease & Venous Disorders

56.1 Chronic Kidney Disease: KDIGO Staging & Renoprotective Therapy 56.2 Chronic Venous Insufficiency, Stasis Dermatitis & Lymphedema 56.3 Chronic Electrolyte & Acid-Base Management in CKD

57 Chapter 57: Chronic Gastrointestinal & Hepatic Diseases

57.1 Gastroesophageal Reflux Disease, Barrett's Esophagus & Dyspepsia 57.2 Chronic Liver Disease: MASLD/NAFLD, Cirrhosis & Portal Hypertension 57.3 Viral Hepatitis B & C: Long-Term Monitoring & DAA Therapy

58 Chapter 58: Colorectal Surveillance & Chronic Pancreaticobiliary Care

58.1 Post-Polypectomy Colorectal Polyp Surveillance Guidelines 58.2 Chronic Pancreatitis & Exocrine Pancreatic Insufficiency 58.3 Chronic Nausea, Gastroparesis & Functional GI Disorders

59 Chapter 59: Chronic Musculoskeletal & Rheumatologic Disorders

59.1 Osteoarthritis: Hip, Knee & Hand Management 59.2 Spinal Conditions: Spinal Stenosis, Spondylolisthesis & Compression Fractures 59.3 Chronic Myopathies & Fibromyalgia Syndrome

60 Chapter 60: Chronic Neurologic & Neurodegenerative Disorders

60.1 Dementia: Alzheimer's, Vascular & Lewy Body Disease 60.2 Parkinson's Disease & Essential Tremor 60.3 Epilepsy: Chronic Antiseizure Medications & Post-Stroke Care

61 Chapter 61: Chronic Peripheral Nerves, Pain & Sensory Disorders

61.1 Diabetic & Chronic Peripheral Neuropathies 61.2 Chronic Pain Syndromes & Chronic Daily Headaches 61.3 Chronic Tinnitus, Presbycusis & Persistent Dizziness

62 Chapter 62: Chronic Psychiatric Disorders

62.1 Major Depressive Disorder & Generalized Anxiety Disorder 62.2 Bipolar Disorder: Maintenance Pharmacotherapy & Lithium Monitoring 62.3 Adult & Pediatric Attention-Deficit/Hyperactivity Disorder

63 Chapter 63: Chronic Behavioral Health & Neurodevelopmental Conditions

63.1 Chronic Behavioral Conditions: PTSD, OCD & Somatization 63.2 Autism Spectrum Disorder & Intellectual Disabilities 63.3 Eating Disorders: Anorexia Nervosa, Bulimia & Binge Eating

64 Chapter 64: Chronic Substance Use Disorders & Tobacco Cessation

64.1 Alcohol Use Disorder: Pharmacotherapy & Relapse Prevention 64.2 Opioid & Stimulant Use Disorders: MOUD & Harm Reduction 64.3 Longitudinal Tobacco Cessation Pharmacotherapy

65 Chapter 65: Chronic Dermatologic Conditions

65.1 Acne Vulgaris, Rosacea & Seborrheic Dermatitis 65.2 Chronic Plaque Psoriasis & Biologic Therapies 65.3 Chronic Eczema, Hidradenitis Suppurativa & Cutaneous Lupus

66 Chapter 66: Chronic Reproductive, Infectious & Geriatric Special Care

66.1 Chronic Menstrual Disorders, Infertility & Sexual Dysfunction 66.2 Menopause Management & Hormone Replacement Therapy 66.3 Chronic HIV Infection Management & Primary Care Integration 66.4 Gender-Affirming Primary Care & Hormone Therapy 66.5 Advance Care Planning, Palliative Care & End-of-Life Symptom Control

67 Chapter 67: Continuity Care: Sleep, Fatigue, Cancer, Pregnancy & the Adult Preventive Visit

67.1 Chronic Insomnia & Obstructive Sleep Apnea 67.2 Chronic Malaise, Fatigue & ME/CFS 67.3 Primary Care During Cancer Treatment & Survivorship 67.4 Routine Prenatal Care & Longitudinal Pregnancy Management 67.5 The Periodic Adult Health Examination & Medicare Annual Wellness Visit

39.1 Atopic Dermatitis, Contact Dermatitis & Eczematous Flares

Key Takeaways Explain This Topic AI

Atopic dermatitis is driven by epidermal skin barrier failure from loss-of-function filaggrin (FLG) gene mutations combined with a Th2-skewed immune response (IL-4, IL-13, IL-31); clinical morphology evolves by age: infancy (<2 years) features exudative crusted papules and plaques on cheeks and extensors while strictly sparing the diaper area, whereas childhood and adulthood display dry, lichenified flexural plaques in antecubital and popliteal fossae.

First-line baseline maintenance requires aggressive emollient barrier restoration ('soak and seal' with thick petrolatum- or ceramide-based ointments within 3 minutes of bathing); acute flares require topical corticosteroids matched to anatomic site risk: low-potency (Class 6-7: hydrocortisone 1-2.5%, desonide 0.05%) for the face, neck, and intertriginous folds; medium-potency (Class 3-5: triamcinolone 0.1%) for the trunk and extremities; and high-potency (Class 1-2: clobetasol 0.05%) for severe lichenified hand/foot plaques for under 2 weeks.

Topical calcineurin inhibitors (tacrolimus 0.03-0.1%, pimecrolimus 1%) provide potent steroid-sparing efficacy without risking cutaneous atrophy, telangiectasias, or ocular hypertension, making them the preferred topical agents for the face, periorbital area, and neck; dupilumab (IL-4R alpha antagonist blocking IL-4 and IL-13) is first-line targeted biologic therapy for moderate-to-severe refractory disease.

Eczema herpeticum (Kaposi varicelliform eruption) is a dermatologic emergency caused by superimposed herpes simplex virus (HSV-1) infection on eczematous skin, presenting with monomorphic, umbilicated vesicles, punched-out hemorrhagic erosions, fever, and adenopathy; immediate oral or intravenous acyclovir/valacyclovir is mandatory to prevent viremic dissemination and blinding herpes keratitis.

Irritant contact dermatitis (ICD) is a non-immunologic physical/chemical barrier disruption with localized burning/stinging exceeding pruritus; allergic contact dermatitis (ACD) is a Type IV delayed hypersensitivity reaction (urushiol, nickel, neomycin) featuring intense pruritus and geometric/linear vesicles; extensive poison ivy (>20% BSA, facial, or genital involvement) requires an oral prednisone taper over 14 to 21 days to prevent explosive rebound flares caused by persistent lipophilic urushiol oleoresin.

Last updated: September 2026

Pathophysiology & Etiology of Atopic Dermatitis

Atopic dermatitis (AD, eczema) is a chronic, relapsing, highly pruritic inflammatory dermatosis that affects up to 15% to 20% of children and 3% to 10% of adults worldwide. It represents the initial cutaneous manifestation of the classic "atopic march" , a predictable developmental sequence progressing from atopic dermatitis in infancy to food allergies, allergic rhinitis, and asthma in childhood and adolescence. PATHOPHYSIOLOGY OF ATOPIC DERMATITIS

Epidermal Barrier Defect Immune Dysregulation (Th2-Skewed)
┌─────────────────────────────┐ ┌─────────────────────────────┐
│ • FLG (Filaggrin) Mutation │ │ • Allergen / Microbial Entry│
│ • Decreased Ceramides │───────>│ • Th2 Cytokines: IL-4, IL-13 │
│ • Increased TEWL (Water Loss)│ │ • IL-31 ("Itch Cytokine") │
│ • Defective Stratum Corneum │ │ • Elevated Serum IgE │
└─────────────────────────────┘ └─────────────────────────────┘
│ │
▼ ▼
┌───────────────────────────────────────────────────────────────────┐
│ THE ITCH-SCRATCH CYCLE │
│ Severe Pruritus ──> Excoriation ──> Barrier Breakdown ──> Flares │
│ Superinfection Risk: Staphylococcus aureus (>90%) & HSV-1 (EH) │
└───────────────────────────────────────────────────────────────────┘
1. Epidermal Skin Barrier Dysfunction

Filaggrin ( FLG ) Gene Mutations : Loss-of-function mutations in the FLG gene (located on chromosome 1q21 within the epidermal differentiation complex) represent the strongest known genetic risk factor for atopic dermatitis. Profilaggrin is cleaved into filaggrin monomers that aggregate keratin filaments, flattening keratinocytes into the rigid stratum corneum "bricks".

Natural Moisturizing Factor (NMF) : Filaggrin breakdown products (amino acids, pyrrolidone carboxylic acid, urocanic acid) constitute NMF, which maintains stratum corneum hydration, skin plasticity, and an acidic cutaneous mantle (pH 4.5-5.5). In FLG deficiency, transepidermal water loss (TEWL) rises dramatically, and cutaneous pH increases, which activates endogenous serine proteases (kallikreins) and degrades lipid-processing enzymes.

Lipid Abnormalities : Deficiencies in intercellular ceramides, sphingosines, and free fatty acids disrupt the extracellular lipid "mortar", leading to microscopic cracking, xerosis, and increased susceptibility to irritants, environmental allergens, and microbes.

2. Th2-Skewed Immune Dysregulation

Epithelial Cytokines : Damaged keratinocytes release alarmins—thymic stromal lymphopoietin (TSLP), interleukin-25 (IL-25), and IL-33—which activate dermal dendritic cells and group 2 innate lymphoid cells (ILC2s).

Th2 Cytokine Cascades : Activated CD4+ T helper 2 (Th2) cells secrete IL-4 and IL-13 , which drive B-cell class-switching to produce immunoglobulin E (IgE) and directly downregulate filaggrin and loricrin expression, creating a vicious cycle of further barrier breakdown.

The "Itch Cytokine" (IL-31) : IL-31 binds directly to the IL-31 receptor A on cutaneous unmyelinated C-fibers, triggering severe, intractable pruritus. Pruritus promotes scratching, which releases additional inflammatory mediators—the quintessential itch-scratch cycle .

3. Environmental Triggers & Colonization

Staphylococcal Colonization : Over 90% of patients with atopic dermatitis exhibit dense cutaneous colonization with Staphylococcus aureus on lesional skin (compared to <5-10% of healthy controls). S. aureus produces enterotoxins (superantigens) that stimulate polyclonal T-cell activation and corticosteroid resistance.

Exogenous Triggers : Low ambient humidity, cold dry winter air, excessive hot water exposure, harsh detergents, wool fabrics, emotional stress, and aeroallergens (dust mites, pet dander).

Clinical Phenotypes & Age-Specific Distribution

The clinical presentation and anatomical distribution of atopic dermatitis evolve characteristically across three distinct life stages. Recognizing these age-dependent patterns is a cornerstone of primary care clinical assessment and board examinations. AGE-SPECIFIC ECZEMA DISTRIBUTION

INFANCY (<2 Years) CHILDHOOD (2-12 Yr) ADULTHOOD (>12 Yr)
┌────────────────────┐ ┌────────────────────┐ ┌────────────────────┐
│ • Cheeks, Forehead │ │ • Flexural Creases │ │ • Lichenification │
│ • Scalp │ │ - Antecubital │ │ • Antecubital/Pop. │
│ • Extensor Limbs │ │ - Popliteal │ │ • Hand Dermatitis │
│ • Weeping / Crusts │ │ • Wrists / Ankles │ │ • Periocular/Neck │
│ • SPARES DIAPER! │ │ • Dry & Excoriated │ │ • Chronic Relapsing│
└────────────────────┘ └────────────────────┘ └────────────────────┘
1. Infancy Stage (Birth to 2 Years)

Onset : Typically presents between 2 and 6 months of age.

Lesion Morphology : Acute, intensely pruritic, erythematous papules and patches with microvesicles, exudative weeping, and serous yellow crusting.

Distribution : Cheeks, forehead, scalp, and extensor surfaces of the extremities (knees, elbows, shins) as crawling infants rub their limbs against carpets and bedding.

Board Exam High-Yield Pearl : Strict sparing of the diaper area ! The occlusive, high-humidity microenvironment under diapers prevents cutaneous xerosis and epidermal barrier desiccation. If an infant presents with an inflammatory, beefy red rash involving the diaper area with satellite pustules, suspect Candida diaper dermatitis; if confluent erythema involves the groin creases, consider irritant contact diaper dermatitis or seborrheic dermatitis, not atopic dermatitis.

2. Childhood Stage (2 Years to Puberty)

Lesion Morphology : Subacute to chronic dry, erythematous, excoriated papules and plaques with marked lichenification (thickening of the epidermis with accentuation of normal skin markings secondary to chronic repetitive scratching).

Distribution : Classic flexural predilection : antecubital and popliteal fossae, volar wrists, anterior ankles, posterior neck, and infra-auricular creases.

Associated Physical Findings :

Dennie-Morgan Folds : Prominent, symmetric infraorbital skin folds caused by persistent ocular rubbing and spasm of the underlying orbicularis oculi muscle;

Allergic Shiners : Dark, violaceous periorbital discoloration secondary to venous stasis;

Pityriasis Alba : Ill-defined, hypopigmented, finely scaly, non-pruritic macules and patches on the cheeks and upper arms, representing post-inflammatory hypopigmentation and mild eczematous dermatitis, commonly noticed after sun exposure;

Keratosis Pilaris : Folliculocentric hyperkeratotic papules ("chicken skin") on the lateral aspects of the upper arms, thighs, and buttocks;

Hyperlinear Palms : Accentuation of palmar skin markings strongly correlated with heterozygous FLG gene mutations.

3. Adolescent & Adult Stage (>12 Years)

Lesion Morphology : Chronic, heavily lichenified, dry, thickened plaques, fissuring, and post-inflammatory hyper- or hypopigmentation.

Distribution : Flexural creases, dorsal hands and wrists (chronic occupational or irritant hand dermatitis), periocular and perioral skin, upper trunk, and nape of neck.

Adult Complications : Sleep fragmentation, severe anxiety, depression, recurrent skin soft-tissue infections, and occupational disability.

Long-Term Barrier Restoration & Flare Prevention

The foundation of atopic dermatitis management is continuous, proactive barrier repair and elimination of cutaneous irritants. Pharmacologic therapies fail if underlying barrier dysfunction is neglected.

The "Soak and Seal" Regimen

Bathing Technique : Patients should take once-daily lukewarm baths or showers lasting 5 to 10 minutes. Avoid hot water, which leaches intercellular lipids and triggers mast cell histamine release.

Soap Substitutes : Strictly avoid traditional alkaline bar soaps (pH 9.0-10.0), which elevate skin surface pH and activate degradative proteases. Recommend mild, synthetic detergent-based liquid cleansers (syndets) with an acidic or neutral pH (pH 5.5-7.0), applied sparingly to the axillae and groin only.

The 3-Minute Rule ("Soak and Seal") : Within 3 minutes of exiting the bath, while the stratum corneum is fully hydrated, pat the skin gently with a soft towel (leaving it slightly damp) and immediately apply a generous layer of emollient to the entire body to lock in moisture.

Emollient Selection Hierarchy

Ointments (First-Line / Most Effective) : Anhydrous, petrolatum-based formulations (e.g., white petrolatum, Aquaphor). They provide superior lipid barrier occlusion and minimal water evaporation. Because they contain no water, they require no chemical preservatives, minimizing allergic contact sensitization.

Creams (Second-Line) : Water-in-oil emulsions with moderate lipid content. Cosmetically acceptable for daytime use or warmer climates, but require chemical preservatives that may cause transient stinging on inflamed skin.

Lotions (Contraindicated / Avoid in Eczema) : High water and alcohol content with low lipid content. Lotions evaporate rapidly, worsening cutaneous xerosis through evaporative water loss, and contain fragrances and preservatives that provoke contact sensitization.

Dilute Bleach Baths (Sodium Hypochlorite)

For patients with recurrent, frequent bacterial superinfections, dilute sodium hypochlorite baths reduce S. aureus skin bioburden and suppress cutaneous NF-kB-mediated inflammation.

Recipe : Add 1/2 cup (120 mL) of standard 6% household bleach to a full 40-gallon bathtub of lukewarm water (achieving an approximate concentration of 0.005%), soaking for 10 minutes 2 to 3 times weekly, followed by clean water rinsing and immediate emollient sealing.

Topical Pharmacotherapy & Corticosteroid Hierarchy

When non-pharmacologic barrier restoration is insufficient, topical anti-inflammatory pharmacotherapy is indicated for acute flares and proactive maintenance.

Topical Corticosteroid (TCS) Potency Hierarchy

Topical corticosteroids are categorized into 7 potency classes based on cutaneous vasoconstrictor assays (Class 1 = superpotent; Class 7 = lowest potency).

Class Potency Representative Agents & Formulations Recommended Clinical Indications & Safety Rules

Class 1 Superpotent Clobetasol propionate 0.05% (cream, ointment); Betamethasone dipropionate augmented 0.05% Severe, thick, hyperkeratotic, chronic lichenified plaques on palms and soles .; • Max duration: <2 consecutive weeks .; • Max dose: 50 g/week.; • STRICTLY CONTRAINDICATED on face, neck, groin, axillae, or in infants!

Class 2 Potent Fluocinonide 0.05%; Desoximetasone 0.25% Severe chronic flares on trunk and extremities refractory to medium-potency agents. Limit use to 2-3 weeks.

Class 3-5 Medium Potency Triamcinolone acetonide 0.1%; Mometasone furoate 0.1%; Betamethasone valerate 0.1% Workhorse agents for acute flares on trunk and extremities in adults and older children.; • Safe for short courses (2-4 weeks).; • Avoid on thin skin folds and face.

Class 6-7 Low Potency Hydrocortisone 1.0%, 2.5%; Desonide 0.05% First-line for delicate and thin skin : Face, eyelids, perioral area, neck, axillae, groin, scrotum, and infants.; • Low risk of cutaneous atrophy; safe for 2-4 weeks.

Cutaneous & Systemic Adverse Effects of TCS

Local Adverse Effects : Epidermal and dermal atrophy, irreversible striae distensae (especially in axillae and groin), telangiectasias, purpura, perioral dermatitis, rosacea-like rebound flares, and hypopigmentation.

Ocular Complications : Long-term application of medium- or high-potency corticosteroids to the periorbital skin can cause increased intraocular pressure, open-angle glaucoma, and posterior subcapsular cataracts.

Systemic Absorption : Extensive application of high-potency steroids over large body surface areas (especially under occlusion or in infants with high surface-area-to-body-mass ratios) can lead to hypothalamic-pituitary-adrenal (HPA) axis suppression , iatrogenic Cushing syndrome, and pediatric growth impairment.

Topical Calcineurin Inhibitors (TCIs): The Steroid-Sparing Gold Standard

Mechanism of Action : Tacrolimus (0.03% ointment for children 2-15 years; 0.1% ointment for adults) and Pimecrolimus (1% cream) bind to intracellular immunophilin FKBP-12, forming a complex that inhibits calcineurin phosphatase. This prevents dephosphorylation of the nuclear factor of activated T-cells (NFAT), blocking transcription of proinflammatory cytokines (IL-2, IL-3, IL-4, IFN-gamma) and downregulating T-cell activation.

Clinical Indications :

First-line steroid-sparing therapy for sensitive, thin-skinned anatomic sites: face, eyelids, periocular skin, neck, and intertriginous folds .

Proactive maintenance therapy: applied twice weekly to previously affected sites to prevent recurrent flares.

Safety Advantages : TCIs do NOT inhibit collagen synthesis and therefore cause zero cutaneous atrophy, striae, or telangiectasias , and do not increase intraocular pressure when applied to eyelids.

Patient Counseling : Clinicians must warn patients that TCIs frequently cause localized transient burning, warmth, and stinging during the first 3 to 5 days of application. This burning sensation resolves as cutaneous inflammation improves. Storing the tube in the refrigerator prior to application minimizes stinging.

FDA Boxed Warning Pearl : Although TCIs carry an FDA boxed warning regarding theoretical risk of lymphoma and skin malignancies, extensive 10-year post-marketing registry data (APPLES study) have confirmed no increased incidence of malignancy compared to the general population.

Topical PDE-4 & JAK Inhibitors

Crisaborole 2% Ointment : A boron-based topical phosphodiesterase-4 (PDE-4) inhibitor approved for mild-to-moderate atopic dermatitis in patients >=3 months of age. PDE-4 inhibition elevates intracellular cyclic AMP (cAMP), suppressing NF-kB and downregulating proinflammatory cytokine release.

Ruxolitinib 1.5% Cream : A topical Janus kinase (JAK1/JAK2) inhibitor approved for short-term and non-continuous chronic treatment of mild-to-moderate AD in non-immunocompromised patients >=12 years. Provides rapid antipruritic relief within 24 to 48 hours.

Advanced Systemic Biologics & Emerging Therapies

For patients with moderate-to-severe atopic dermatitis whose disease remains uncontrolled despite optimized topical barrier repair and topical pharmacotherapies, systemic targeted biologic therapy is the standard of care.

Dupilumab (Anti-IL-4R-alpha)

Mechanism : A fully human IgG4 monoclonal antibody that binds specifically to the shared IL-4 receptor alpha (IL-4R-alpha) subunit , simultaneously inhibiting signaling of both IL-4 and IL-13 through the Type I and Type II receptor complexes.

Indications : Approved for moderate-to-severe atopic dermatitis in adults and pediatric patients down to 6 months of age.

Dosing (Adults) : Initial loading dose of 600 mg subcutaneously (two 300 mg injections), followed by 300 mg subcutaneously every 2 weeks.

Efficacy : Produces rapid, dramatic reductions in pruritus, marked improvement in Eczema Area and Severity Index (EASI-75) scores, and substantial restoration of the epidermal barrier without organ toxicity.

Adverse Effects : Injection site reactions, transient blood eosinophilia, and conjunctivitis / blepharitis (occurs in 10% to 20% of eczema patients on dupilumab, responsive to lubricating eye drops, fluorometholone ophthalmic drops, or tacrolimus 0.03% ophthalmic ointment).

Other Biologics & Oral JAK Inhibitors

Tralokinumab : Monoclonal antibody neutralizing IL-13 specifically, approved for moderate-to-severe AD in adults.

Oral JAK Inhibitors (Upadacitinib, Abrocitinib) : Highly effective oral small-molecule inhibitors of JAK1 offering rapid disease clearance, but carrying class boxed warnings (major adverse cardiovascular events, thrombosis, serious infections, malignancies) requiring baseline laboratory screening.

Infectious Complications: Superinfections & Eczema Herpeticum

Compromised physical barriers, decreased antimicrobial peptides (cathelicidins and beta-defensins), and intense scratching predispose atopic individuals to secondary cutaneous infections. ECZEMA INFECTIOUS COMPLICATIONS

BACTERIAL (Staphylococcus aureus) VIRAL: ECZEMA HERPETICUM (HSV-1)
┌────────────────────────────────┐ ┌────────────────────────────────┐
│ • Honey-colored crusts │ │ • DERMATOLOGIC EMERGENCY! │
│ • Pustules, purulent exudate │ │ • Monomorphic umbilicated │
│ • Impetiginization of eczema │ │ vesicles / punched-out sores │
│ • Rx: Topical Mupirocin OR │ │ • Fever, chills, adenopathy │
│ Oral Cephalexin / TMP-SMX │ │ • Emergency IV/Oral Acyclovir! │
└────────────────────────────────┘ └────────────────────────────────┘
1. Bacterial Superinfection (Secondary Impetiginization)

Microbiology : Staphylococcus aureus (methicillin-sensitive or MRSA) and Streptococcus pyogenes (Group A Strep).

Clinical Presentation : Sudden worsening of baseline eczema, accompanied by honey-colored (meliceric) crusting , painful follicular pustules, weeping purulent exudate, and regional lymphadenopathy.

Management :

Localized superficial crusting: Topical Mupirocin 2% ointment three times daily for 5 to 7 days.

Widespread or systemic involvement: Oral systemic antibiotics with anti-staphylococcal coverage: Cephalexin 500 mg QID (or dicloxacillin) for MSSA; Trimethoprim-Sulfamethoxazole (TMP-SMX 1-2 DS tabs BID) or Doxycycline 100 mg BID for suspected community-acquired MRSA.

2. Eczema Herpeticum (Kaposi Varicelliform Eruption)

Pathophysiology : A potentially life-threatening dermatologic emergency resulting from the acute, widespread dissemination of Herpes Simplex Virus (predominantly HSV-1, rarely HSV-2) across damaged, barrier-deficient eczematous skin.

Clinical Presentation :

Rapid eruption of crops of monomorphic, dome-shaped, umbilicated vesicles clustered over active or quiescent eczematous areas (most frequently the head, neck, and upper trunk);

The vesicles rapidly evolve into punched-out, circular, hemorrhagic erosions with scalloped borders that coalesce into large, denuded, oozing areas;

Systemic Symptoms : High fever, rigors, malaise, irritability, and painful regional lymphadenopathy.

Complications : Secondary bacterial sepsis ( S. aureus ), viremic dissemination to the brain, liver, and lungs, and herpes keratoconjunctivitis (corneal ulceration, scarring, and permanent visual loss if periorbital skin is involved).

Diagnostic Confirmation : Clinical diagnosis confirmed by viral PCR swab of vesicular fluid (gold standard) or Tzanck smear demonstrating multinucleated giant cells and Cowdry A inclusion bodies.

Emergency Treatment :

Immediate Antiviral Therapy : Delaying treatment can be catastrophic.

Mild, early outpatient disease: Oral Valacyclovir 1,000 mg TID (or oral acyclovir 400 mg 5 times daily) for 10 to 14 days.

Moderate-to-severe, extensive, toxic, or pediatric disease: Hospital admission and Intravenous Acyclovir 5 to 10 mg/kg every 8 hours until clinical improvement, then transition to oral.

Urgent Ophthalmology Consultation : Mandatory whenever lesions approach the periorbital zone, forehead, or nose to evaluate for dendritic keratitis with fluorescein slit-lamp examination.

Pitfall to Avoid : Never apply topical corticosteroids or calcineurin inhibitors to active eczema herpeticum! Immunosuppressants exacerbate viral replication and fatal systemic dissemination.

Contact Dermatitis: Irritant vs. Allergic

Contact dermatitis comprises acute or chronic inflammatory skin reactions provoked by cutaneous exposure to exogenous chemical, physical, or biological substances. It is divided into two fundamentally distinct mechanisms: Irritant Contact Dermatitis (ICD) and Allergic Contact Dermatitis (ACD).

Diagnostic Feature Irritant Contact Dermatitis (ICD) Allergic Contact Dermatitis (ACD)
Incidence 80% of all contact dermatitis ~20% of all contact dermatitis

Mechanism Non-immunologic direct chemical or physical cytotoxicity to stratum corneum Type IV delayed-type hypersensitivity (cell-mediated, T-cell driven)

Prior Sensitization Not required ; occurs on first exposure if concentration/irritant is strong Strictly required (sensitization phase: 10-14 days; elicitation: 24-72 hours)

Predominant Symptom Burning, stinging, smarting, or pain > pruritus Intense, severe pruritus > pain/burning

Lesion Morphology Dryness, erythema, scaling, cracking, fissuring, glazed or chapped appearance Erythema, edema, grouped vesicles/bullae , weeping, crusting, lichenification

Distribution & Margins Strictly confined to the precise boundaries of contact ("decrescendo" pattern) Extends beyond the contact zone; geographic, artificial, or linear patterns

Common Culprits Frequent handwashing (water/wet work), soaps, harsh detergents, alkalis, solvents, acids Urushiol (poison ivy) , nickel , neomycin, fragrance mix, PPD, acrylates

Diagnostic Gold Standard Clinical diagnosis of exclusion Diagnostic epicutaneous patch testing
Common Contact Allergens & Diagnostic Patch Testing
High-Yield Board Allergens

Urushiol (Toxicodendron genus: Poison Ivy, Poison Oak, Poison Sumac) : The most common cause of ACD in North America. Produces pathognomonic linear arrays of pruritic papules and tense vesicles where plant leaves brushed against exposed skin.

Nickel Sulfate : The most prevalent contact allergen worldwide. Manifests as well-circumscribed eczematous plaques beneath earrings (earlobes) , jean button snaps (periumbilical "belt buckle" dermatitis) , wristwatches, or metal eyeglass frames.

Neomycin & Bacitracin : Common components of over-the-counter "triple antibiotic" ointments. Sensitization frequently develops when patients apply ointment to chronic stasis ulcers, surgical wounds, or lacerations, producing an intense flare misdiagnosed as "worsening wound infection."

Paraphenylenediamine (PPD) : Oxidizing chemical found in permanent hair dyes and "black henna" temporary tattoos . Sensitization causes severe scalp and facial edema or acute vesicular eruptions.

Fragrance Mix & Preservatives : Methylisothiazolinone (MI/MCI) in wet wipes and cosmetics; formaldehyde releasers in lotions.

Diagnostic Patch Testing (Epicutaneous Testing)

Clinical Role : The gold standard for identifying the specific causative allergen in persistent, unexplained, or occupational contact dermatitis.

Procedure : Standardized allergen panels (e.g., T.R.U.E. Test) are applied to unaffected skin on the upper back in hypoallergenic chambers.

Timing of Interpretations :

Patches are left in place for 48 hours , then removed for the initial reading (identifies early reactions);

A second delayed reading is performed at 72 to 96 hours (and occasionally at 7 days). The delayed reading is essential because Type IV cell-mediated reactions require 3 to 4 days to manifest fully.

Critical Test Distinction : Patch testing evaluates Type IV delayed hypersensitivity . In contrast, skin prick testing (prick/puncture) evaluates Type I immediate IgE-mediated hypersensitivity (used for allergic rhinoconjunctivitis, food allergies, and venom anaphylaxis).

Management of Rhus Dermatitis & The 21-Day Oral Steroid Rule

Rhus dermatitis (Toxicodendron / poison ivy dermatitis) accounts for countless primary care visits every spring and summer. Family physicians must recognize the pharmacokinetics of urushiol to prevent undertreatment. RHUS DERMATITIS (POISON IVY) TRIAGE

Assess Severity & BSA Involved
│
┌──────────────────────────┴──────────────────────────┐
▼ ▼
LOCALIZED DISEASE (<20% BSA) EXTENSIVE / SEVERE DISEASE
Spares face, eyes, genitalia • >20% BSA involvement OR
High-Potency Topical Steroid: • Face, eyelids, neck, genitalia OR
Clobetasol 0.05% BID x 10-14 days • Severe blistering & functional deficit
Cool compresses, calamine lotion │
Oral antihistamines for sleep ▼

ORAL PREDNISONE TAPER OVER 14-21 DAYS!

Initial: 0.5 - 1.0 mg/kg/day (40-60 mg)
Taper gradually over 2 to 3 weeks

NEVER GIVE A 6-DAY MEDROL PACK!

Prevents Severe Rebound Flares
The Pathophysiology of Urushiol Persistence

Urushiol is an extremely lipophilic, non-volatile oleoresin. Once absorbed into the stratum corneum and sebaceous lipids, it remains bound to epidermal cell membranes for 2 to 3 weeks , continuously stimulating allergen-specific CD4+ and CD8+ memory T cells.

Contact with plant sap initiates sensitization; washing thoroughly with soap and water within 10 to 15 minutes of exposure can remove unabsorbed resin, but washing after 30 to 60 minutes is ineffective.

The 21-Day Oral Corticosteroid Rule: The Ultimate Board Trap

Caution

THE FATAL BOARD MISTAKE: NEVER PRESCRIBE A SHORT 5- TO 6-DAY MEDROL DOSEPACK FOR POISON IVY! A classic board scenario presents a patient with severe, widespread poison ivy dermatitis involving the face, arms, and legs. Prescribing a standard 6-day methylprednisolone "dose pack" (which tapers from 24 mg down to 0 mg over 6 days) is incorrect medical practice! While the patient improves dramatically during the first 4 to 5 days, the steroid is discontinued while active urushiol antigen is still bound in the skin. This invariably triggers an explosive, severe rebound dermatitis that is often worse than the original presentation. Correct Guideline Regimen : When systemic therapy is indicated, prescribe Oral Prednisone starting at 0.5 to 1.0 mg/kg/day (typically 40 to 60 mg daily) , tapered slowly and steadily over a minimum of 14 to 21 days (2 to 3 full weeks) (e.g., 60 mg daily for 5 days, 40 mg daily for 5 days, 20 mg daily for 5 days, and 10 mg daily for 5 days).