38.3 Viral Cutaneous Infections: Herpes Simplex, Zoster & Molluscum Contagiosum

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

5.1 Dietary Counseling for Obesity & Chronic Disease Prevention 5.2 Exercise Prescription & Physical Activity Counseling 5.3 Genetic Risk Assessment & Family History Counseling

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

38.3 Viral Cutaneous Infections: Herpes Simplex, Zoster & Molluscum Contagiosum

Key Takeaways Explain This Topic AI

Herpes simplex virus (HSV-1 and HSV-2) establishes lifelong latency within sensory nerve ganglia; episodic orofacial herpes is treated with high-dose, short-course oral valacyclovir (2 g BID for 1 day) initiated at the earliest prodrome, whereas primary genital herpes requires valacyclovir 1,000 mg BID for 7-10 days.

Herpes zoster (shingles) results from reactivation of latent varicella-zoster virus (VZV) in sensory ganglia; oral antiviral therapy (valacyclovir 1,000 mg TID for 7 days) must be initiated within 72 hours of rash onset to accelerate healing and reduce acute pain and post-herpetic neuralgia risk.

Cranial nerve zoster emergencies: Herpes zoster ophthalmicus (V1 distribution, Hutchinson sign on nasal tip) mandates same-day ophthalmology referral to prevent corneal ulceration; Ramsay Hunt syndrome (geniculate ganglion, facial palsy + severe otalgia + ear canal vesicles) requires valacyclovir plus oral prednisone.

Post-herpetic neuralgia is neuropathic pain persisting >90 days after rash onset, managed with topical lidocaine patches, gabapentin, pregabalin, or SNRIs/TCAs; Shingrix (recombinant zoster vaccine, 2 doses) provides >90% protection for adults ≥50 years and immunocompromised adults ≥19 years.

Molluscum contagiosum (Poxvirus) causes firm, pearly, dome-shaped umbilicated papules; it is benign and self-limiting (clearing spontaneously over 6 to 18 months), with watchful waiting recommended as first-line in children, while active destructive modalities are reserved for symptomatic, cosmetically distressing, or genital lesions.

Last updated: September 2026

Herpes Simplex Virus Infections (HSV-1 & HSV-2)

Herpes simplex viruses (HSV-1 and HSV-2) are double-stranded DNA viruses belonging to the Herpesviridae family. They are characterized by neurovirulence, primary mucocutaneous infection, and the establishment of lifelong latency within sensory nerve ganglia with episodic reactivations.

Virology, Pathogenesis & Latency

Transmission : Occurs via direct contact with active mucocutaneous lesions or through asymptomatic viral shedding in bodily secretions (saliva, genital secretions) from an infected host.

Establishment of Latency : Following initial mucosal or cutaneous inoculation and local epidermal replication, viral particles enter unmyelinated sensory nerve endings and ascend along sensory axons via retrograde intra-axonal transport to the sensory neuron cell bodies located in sensory ganglia:

Trigeminal Ganglion (CN V) : Primary reservoir of latency for HSV-1 (responsible for recurrent orofacial herpes);

Sacral Dorsal Root Ganglia (S2 to S4) : Primary reservoir of latency for HSV-2 (responsible for recurrent genital herpes), though HSV-1 increasingly establishes sacral latency following orogenital contact.

Reactivation : Latent viral genomes persist as non-integrated episomal circular DNA in sensory neurons. Physical or emotional stimuli—ultraviolet radiation, fever, psychological stress, tissue trauma, surgical manipulation, immunosuppression, or hormonal fluctuations during menses—trigger viral reactivation. Viral particles travel down sensory nerves via anterograde intra-axonal transport back to the epithelial surface, producing recurrent cutaneous vesicles or asymptomatic shedding.

Clinical Manifestations of HSV HERPES SIMPLEX CLINICAL MANIFESTATIONS

• Syndrome Primary Features Evidence-Based Therapy
• ─────────────────────────────────────────────────────────────────────────────
• Orofacial Herpes Prodrome (tingling/burning) ────> Oral Valacyclovir 2,000 mg
• (Herpes Labialis) Grouped clear vesicles on an BID for 1 single day
• erythematous base at vermilion (Initiate at earliest prodrome)

border; crusts in 7-10 days.

• ─────────────────────────────────────────────────────────────────────────────
• Primary Genital Severe bilateral painful ulcers, Oral Valacyclovir 1,000 mg
• Herpes tender inguinal lymphadenopathy, PO BID for 7 to 10 days
• dysuria, fever, malaise (2-3 wk). (or Acyclovir 400 mg TID)
• ─────────────────────────────────────────────────────────────────────────────
• Recurrent Genital Milder unilateral lesions (4-6 d); Oral Valacyclovir 500 mg BID
• Herpes neuralgic prodrome in buttocks for 3 days (patient-initiated)
• or thighs. OR Daily suppressive therapy
• ─────────────────────────────────────────────────────────────────────────────
• Herpetic Whitlow Painful grouped vesicles on pulp Oral Valacyclovir 1,000 mg TID
• of terminal digit; mistaken for SURGICAL INCISION STRICTLY

felon/paronychia. CONTRAINDICATED!

• ─────────────────────────────────────────────────────────────────────────────
• Eczema Herpeticum Widespread punched-out umbilicated Prompt systemic IV or oral
• (Kaposi Eruption) vesicles on atopic dermatitis; Acyclovir / Valacyclovir;

high fever; MEDICAL EMERGENCY! monitor for secondary sepsis.

1. Orofacial Herpes (Herpes Labialis / "Cold Sores")

Over 80% to 90% are caused by HSV-1. Infection begins with a localized sensory prodrome of tingling, burning, pruritus, or hyperesthesia lasting 6 to 24 hours.

The eruptive phase features a cluster of painful, uniform, grouped vesicles on an erythematous base located at the cutaneous vermilion border of the lip.

The thin-walled vesicles rapidly rupture, ulcerate, exude serous exudate, and form yellowish crusts that resolve completely in 7 to 10 days without scarring.

Treatment of Herpes Labialis :

First-Line Oral Episodic Regimen : Oral Valacyclovir 2,000 mg (2 g) PO twice daily (12 hours apart) for 1 single day (total 4 grams).

Timing : Must be self-initiated by the patient at the very first onset of prodromal tingling to achieve maximal therapeutic benefit.

Alternative Oral : Famciclovir 1,500 mg PO as a single dose.

Topical Limitations : Topical antiviral creams (acyclovir 5% cream, docosanol 10% OTC) reduce episode duration by only 10 to 18 hours (~0.5 day) and are significantly inferior to oral valacyclovir.

2. Genital Herpes Simplex

Primary Genital Episode :

Characterized by widespread, bilateral, multiple, exquisitely painful vesicular and ulcerative lesions on the labia, penis, perineum, or perianal skin.

Accompanied by severe dysuria, vaginal/urethral discharge, marked bilateral tender inguinal lymphadenopathy, and prominent systemic symptoms (fever, headache, myalgias) lasting 2 to 3 weeks.

Regimen : Oral Valacyclovir 1,000 mg PO BID for 7 to 10 days (extend if lesions are not fully healed) or Oral Acyclovir 400 mg PO TID for 7 to 10 days .

Recurrent Genital Episodes :

Manifest as localized, unilateral, milder clusters of vesicles that heal rapidly within 4 to 6 days.

Episodic Therapy : Patient-initiated within 24 hours of prodrome: Oral Valacyclovir 500 mg PO BID for 3 days or 1,000 mg PO daily for 5 days.

Daily Suppressive Therapy : Indicated for patients with frequent recurrences (≥6 episodes per year) , severe psychosocial distress, or to minimize viral transmission to an uninfected partner:

• Oral Valacyclovir 500 mg PO once daily (increase to 1,000 mg daily in patients with >9 recurrences per year);
• Alternative : Oral Acyclovir 400 mg PO BID;

Clinical Impact : Daily suppressive therapy reduces symptomatic clinical outbreaks by 70% to 80% and decreases heterosexual partner transmission by approximately 50% (combined with consistent condom use).

3. Special Clinical Variants of HSV

Herpetic Whitlow :

Painful, vesicular infection involving the distal volar pulp or paronychial folds of a finger or thumb.

Occurs in healthcare personnel (dental workers, respiratory therapists) exposed to infected oral secretions (HSV-1), or in young children with primary herpetic gingivostomatitis who suck their fingers. In adults, it is often caused by digital-genital contact (HSV-2).

Presents with intense throbbing pain, localized erythema, edema, and deep-seated, clear or turbid grouped vesicles.

Caution

SURGICAL CONTRAINDICATION : Herpetic whitlow is frequently misdiagnosed as a bacterial paronychia or deep digital space felon. SURGICAL INCISION AND DRAINAGE IS STRICTLY CONTRAINDICATED ! Incision fails to release pus, leads to delayed wound healing, introduces severe secondary bacterial superinfection, and increases the risk of autoinoculation. Management is strictly medical with oral valacyclovir 1,000 mg PO TID for 7 to 10 days and dry protective dressings.

Eczema Herpeticum (Kaposi Varicelliform Eruption) :

Severe, widespread, disseminated cutaneous HSV infection occurring in individuals with pre-existing skin barrier dysfunction, most commonly atopic dermatitis .

Manifests as an extensive, explosive eruption of uniform, "punched-out," monomorphic, umbilicated vesicles and shallow erosions clustered in areas of active or inactive eczema (especially the face, neck, and upper trunk), accompanied by high fever, malaise, and regional lymphadenopathy.

Represents a dermatologic emergency carrying a significant risk of secondary staphylococcal bacteremia, ocular dissemination, and death. Requires prompt hospitalization, IV or high-dose oral acyclovir/valacyclovir, and empiric antistaphylococcal coverage.

Herpes Zoster (Shingles)

Herpes zoster (shingles) is a localized, neurocutaneous disease caused by the reactivation of endogenous Varicella-Zoster Virus (VZV) that has remained dormant within cranial nerve sensory ganglia or spinal dorsal root ganglia following primary varicella infection (chickenpox).

Pathophysiology & Risk Factors

Mechanism : Declining VZV-specific cell-mediated immunity allows latent virus in dorsal root ganglia to replicate, producing acute ganglionitis and neuronal necrosis. Infectious virions travel down the sensory nerve axon to the corresponding cutaneous dermatome.

Risk Factors : The primary risk factor is advancing age (incidence rises sharply after age 50, with a lifetime risk approaching 30% to 50% by age 85). Other major risk factors include immunosuppression (organ transplantation, hematologic malignancies, chemotherapy, HIV infection with CD4 <200), chronic systemic corticosteroids, autoimmune diseases, and physical trauma.

Clinical Presentation & Staging

Pre-eruptive Dermatomal Prodrome (Days 1 to 5) :

Burning, lancinating, throbbing, shooting, or electric shock-like neuropathic pain, hyperesthesia, paresthesias, and tactile allodynia localized strictly within a single unilateral dermatome .

Systemic symptoms (low-grade fever, malaise, headache) occur in 20% of patients.

Diagnostic Trap : Dermatomal pain preceding the rash frequently mimics acute visceral emergencies: thoracic zoster mimics myocardial infarction or acute pleurisy; lower thoracic/lumbar zoster mimics acute cholecystitis, appendicitis, or renal colic; lumbosacral zoster mimics acute sciatica or lumbar disc herniation.

Acute Eruptive Phase (Days 3 to 10) :

Erythematous macules and papules erupt rapidly, evolving within 24 hours into grouped, clear, tense vesicles on an erythematous base .

Cardinal Feature : The rash is strictly unilateral and distributed in a dermatomal band , respecting the anatomical midline of the body. The most common sites are thoracic dermatomes (T3 to L2, >50% of cases), followed by cranial nerve dermatomes (predominantly the ophthalmic V1 division of the trigeminal nerve) and cervical dermatomes.

Over 3 to 5 days, vesicles become pustular, umbilicated, and turbid, then rupture to form crusts by day 7 to 10.

Crusting & Resolution (Weeks 2 to 4) :

Lesions are completely crusted and no longer infectious within 10 to 14 days, with complete cutaneous healing occurring over 2 to 4 weeks, often leaving transient hypopigmentation, hyperpigmentation, or scarring.

Disseminated Herpes Zoster :

Defined as more than 20 discrete vesicular lesions occurring outside the primary and immediately adjacent dermatomes , or zoster with visceral organ involvement (pneumonitis, hepatitis, encephalitis).

Occurs almost exclusively in severely immunocompromised hosts. Demands immediate inpatient hospital admission, intravenous acyclovir (10 mg/kg IV every 8 hours) , and combined airborne and contact isolation.

Antiviral Management of Acute Herpes Zoster ACUTE HERPES ZOSTER THERAPY

• Drug Standard Dose Renal Adjustment (CrCl <50 mL/min)
• ─────────────────────────────────────────────────────────────────────────────
• VALACYCLOVIR 1,000 mg PO TID for 7 days CrCl 30-49: 1,000 mg PO q12h
• (Preferred) CrCl 10-29: 1,000 mg PO q24h
• CrCl <10: 500 mg PO q24h
• ─────────────────────────────────────────────────────────────────────────────
• FAMCICLOVIR 500 mg PO TID for 7 days CrCl 40-59: 500 mg PO q12h
• CrCl 20-39: 500 mg PO q24h
• CrCl <20: 250 mg PO q24h
• ─────────────────────────────────────────────────────────────────────────────
• ACYCLOVIR 800 mg PO 5 times daily CrCl 10-25: 800 mg PO q8h
• for 7 days CrCl <10: 800 mg PO q12h

Therapeutic Window : Antiviral therapy should ideally be initiated within 72 hours of rash onset . Oral antivirals accelerate cutaneous healing, halt the formation of new vesicles, shorten the duration of viral shedding, and reduce the intensity and duration of acute pain.

Treating Beyond 72 Hours : Antiviral therapy is still strongly indicated beyond 72 hours if:

• New vesicles are actively continuing to form (indicating persistent ongoing viral replication);
• The patient is ≥50 years of age with ongoing severe pain or extensive cutaneous involvement;
• The patient is immunocompromised ;

The infection involves the eye ( Herpes Zoster Ophthalmicus ) or ear ( Ramsay Hunt syndrome ).

Renal Dosing & Neurotoxicity Warning : Acyclovir and its prodrug valacyclovir are eliminated primarily by renal glomerular filtration and tubular secretion. Failure to adjust dosages in patients with renal impairment results in acyclovir-induced neurotoxicity (manifesting as tremors, confusion, visual hallucinations, myoclonus, encephalopathy, and coma) and acute crystal nephropathy (due to intratubular crystal precipitation; prevented by maintaining aggressive oral or IV hydration).

• Critical Complications of Herpes Zoster
• 1. Herpes Zoster Ophthalmicus (HZO)

Anatomy : Reactivation of VZV in the ophthalmic division (V1) of the trigeminal nerve, accounting for 10% to 15% of all zoster cases.

The Hutchinson Sign : The presence of grouped herpetic vesicles on the tip, side, or root of the nose (ala nasi) . The cutaneous tip of the nose is innervated by the external nasal branch of the nasociliary nerve , which also provides sensory innervation to the cornea, ciliary body, and iris . Crucial Board Pearl : A positive Hutchinson sign predicts intraocular corneal involvement in over 75% to 80% of patients !

Ocular Pathology : Epithelial keratitis, anterior uveitis/iritis, stromal keratitis, secondary glaucoma, scleritis, optic neuritis, and permanent visual loss.

Slit-Lamp Examination : Fluorescein staining reveals classic dendritic pseudodendrites —mucous plaques with tapered, blunt ends and lack of terminal bulbar bulbs (which differentiates them from the delicate, true branching dendrites with terminal bulbs characteristic of HSV keratitis).

Management Pathway :

• Immediate SAME-DAY Ophthalmology Consultation ;
• Oral Valacyclovir 1,000 mg PO TID for 7 to 10 days initiated immediately;
• Urgent slit-lamp biomicroscopy and intraocular pressure measurement;

Strict Warning : Topical ophthalmic corticosteroids must NEVER be prescribed by primary care clinicians without direct in-person ophthalmology evaluation, as steroids cause fulminant corneal melting and perforation in active viral epithelial disease.

2. Ramsay Hunt Syndrome (Herpes Zoster Oticus)

Anatomy : Reactivation of latent VZV within the geniculate ganglion of the facial nerve (Cranial Nerve VII) , frequently involving adjacent fibers of the vestibulocochlear nerve (CN VIII).

The Classical Diagnostic Triad :

Ipsilateral lower motor neuron facial nerve palsy (complete unilateral facial paralysis: inability to close the eye, loss of nasolabial fold, forehead weakness, oral drooping);

Severe, agonizing otalgia (deep ear pain);

Painful vesicular eruption located on the external auditory canal, pinna, concha of the auricle, or anterior two-thirds of the tongue and soft palate.

Associated Manifestations : Sensorineural hearing loss, vertigo, nausea/vomiting, nystagmus, tinnitus, and loss of taste (dysgeusia).

Management :

High-dose Oral Valacyclovir 1,000 mg PO TID for 7 to 10 days ;

PLUS Oral Prednisone (60 mg daily for 5 days, followed by a 5-day taper to 10 mg daily; total 10 to 14 days) to reduce acute edema and ischemia of the facial nerve within the rigid bony fallopian canal;

Aggressive corneal eye protection (artificial tears by day, lubricating ophthalmic ointment and moisture chambers/protective eye taping by night) to prevent exposure keratitis;

Prognosis : Complete facial nerve functional recovery occurs in only 50% to 60% of Ramsay Hunt cases (substantially worse than the ~85-90% recovery rate seen in idiopathic Bell's palsy).

3. Post-Herpetic Neuralgia (PHN)

Definition : Clinically significant, debilitating neuropathic pain that persists for >90 days (3 months) after the onset of the acute herpes zoster rash .

Pathophysiology : Severe inflammatory axonal injury and continuous firing of damaged sensory nociceptive neurons in the dorsal root ganglion, combined with central sensitization in the spinal cord dorsal horn.

Clinical Presentation : Constant deep burning, aching, or throbbing pain, paroxysms of lancinating or electric shock-like sensations, and profound tactile allodynia (where light, non-painful touch—such as clothing brushing the skin or a gentle breeze—provokes agonizing, excruciating pain).

Risk Factors : Age ≥50 years (the single most potent predictor; >50% incidence in patients >80 years of age), severe prodromal pain, severe acute rash density, and ophthalmic (V1) distribution.

First-Line Pharmacologic Management of PHN :

Gabapentinoids :

Gabapentin : Initiate at 300 mg PO at bedtime; titrate upward gradually by 300 mg every 3 to 5 days to a therapeutic target of 1,800 to 3,600 mg/day divided TID . Doses must be reduced in renal insufficiency;

Pregabalin : Initiate at 75 mg PO BID; titrate to 150 mg BID within 1 week, up to maximum 300 mg BID.

Topical Lidocaine 5% Patch : Apply up to 3 patches simultaneously over the area of maximal intact painful allodynic skin for 12 hours on, 12 hours off daily. Excellent first-line choice for localized allodynia, providing rapid relief with zero systemic adverse effects.

Tricyclic Antidepressants (TCAs) : Nortriptyline or Amitriptyline 10 to 25 mg PO at bedtime, slowly titrated up to 75 to 100 mg at bedtime. Nortriptyline is preferred over amitriptyline due to fewer sedating and anticholinergic adverse effects. Caution : Avoid in elderly patients with pre-existing cardiac conduction disease (arrhythmias, QT prolongation), glaucoma, urinary retention, or severe fall risk.

Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs) : Duloxetine 60 mg PO once daily (titrate up to 120 mg/day).

Topical Capsaicin : High-concentration (8%) capsaicin dermal patch (in-office application) or low-concentration cream (0.025-0.075% applied QID); depletes substance P from local nociceptors.

Prevention: Recombinant Zoster Vaccine (Shingrix)

Vaccine Composition : A non-live, recombinant subunit vaccine containing VZV glycoprotein E combined with the AS01B adjuvant suspension system.

ACIP & CDC Recommendations :

Recommended as a 2-dose series (dose 2 administered intramuscularly 2 to 6 months after dose 1);

Indicated for ALL immunocompetent adults aged ≥50 years , regardless of whether they have a prior history of chickenpox, prior episode of shingles, or prior receipt of the historic live-attenuated zoster vaccine (Zostavax);

Indicated for immunocompromised adults aged ≥19 years who are or will be at increased risk of zoster;

Efficacy : Provides >90% efficacy in preventing herpes zoster and post-herpetic neuralgia across all age cohorts, with sustained efficacy documented beyond 10 years;

Note : The live-attenuated vaccine (Zostavax) was permanently discontinued in the United States in November 2020.

Molluscum Contagiosum

Molluscum contagiosum is a common, benign, superficial cutaneous viral infection caused by the Molluscum Contagiosum Virus (MCV) , a large, double-stranded DNA virus of the Poxviridae family.

Virology & Histopathology

Cellular Tropism : MCV replicates exclusively within the cytoplasm of epidermal keratinocytes. It does not establish latency, produce systemic viremia, or invade the dermis.

Histopathology : Characteristic Henderson-Paterson bodies (molluscum bodies)—large, dense, intracytoplasmic, eosinophilic-to-basophilic inclusion bodies that displace the host keratinocyte nucleus to the cell periphery within the stratum spinosum and corneum.

Transmission & Epidemiology

Modes of Transmission : Direct skin-to-skin contact, autoinoculation via scratching (producing linear arrangements of lesions along excoriation tracks, known as the pseudo-Koebner phenomenon ), and indirect transmission via fomites (shared bath towels, washcloths, clothing, wrestling mats, contaminated pool toys).

Two Primary Affected Demographics :

Pediatric Population (Ages 1 to 10 years) : The most frequent clinical demographic. Lesions are located predominantly on the trunk, intertriginous flexures (axillae, antecubital fossae, popliteal fossae), face, and extremities ;

Young Adults (Sexually Active) : Transmitted as a sexually transmitted infection (STI) . Lesions are clustered on the groin, pubic region, lower abdomen, upper inner thighs, and genitalia .

Immunocompromised Host Presentation : In patients with advanced HIV/AIDS (CD4 count <200 cells/mcL), hematologic malignancy, or profound T-cell immunosuppression, molluscum presents with atypical, extensive disease: giant mollusca (>1 cm in diameter) , extensive facial distribution, or hundreds of widespread, disfiguring, recalcitrant lesions that fail standard therapies.

Clinical Presentation & The "BOTE" Sign

Physical Exam Findings :

Discrete, smooth, firm, dome-shaped, flesh-colored, pink, or translucent pearly papules measuring 1 to 5 mm in diameter .

Hallmark Finding : Central umbilication featuring a small dimple or pit on the summit of the papule.

Gentle lateral compression of a mature papule expresses a central, solid, white, curd-like or cheesy core consisting of compacted keratin and millions of infectious virions.

Molluscum Dermatitis : Up to 30% of children develop a localized, intensely pruritic, eczematous dermatitis surrounding molluscum papules, which is an inflammatory reaction to viral antigens rather than secondary bacterial infection.

The BOTE Sign ("Beginning Of The End") :

Individual molluscum papules frequently become markedly erythematous, swollen, fluctuant, and crusted, appearing clinically "infected."

Clinical Pearl : This inflammatory flare indicates that the host's cell-mediated immune system has successfully recognized the poxvirus antigens and is actively clearing the lesion ! It is known clinically as the BOTE sign ("beginning of the end") . Clinicians must reassure parents that this erythema represents natural immune-mediated resolution rather than secondary bacterial cellulitis; antibiotics are strictly unnecessary .

Evidence-Based Management Strategy MOLLUSCUM CONTAGIOSUM MANAGEMENT

• Patient Category Clinical Strategy Rationale & Interventions
• ─────────────────────────────────────────────────────────────────────────────
• Pediatric Uncomplicated WATCHFUL WAITING & • Benign, self-limiting
• (Most children) OBSERVATION • Resolves spontaneously in 6-18 mo
• (First-line standard) • Avoid pain, fear, & scarring of
• destructive procedures
• Counsel: do not share towels
• ─────────────────────────────────────────────────────────────────────────────
• Symptomatic / Active DESTRUCTIVE or CHEMICAL • Indicated for disfigurement,
• Therapy Desired PROCEDURES severe pruritus, or transmission
• (Shared decision-making) • Options: Cantharidin 0.7%,
• Cryotherapy, Curettage
• ─────────────────────────────────────────────────────────────────────────────
• Adult Genital Lesions ACTIVE INTERVENTION + • Cryotherapy / cantharidin to prevent
• (Sexually transmitted) COMPREHENSIVE STI sexual transmission to partners
• SCREENING • Order HIV, Syphilis (RPR),
• Gonorrhea & Chlamydia NAAT

Watchful Waiting (First-Line Standard of Care in Children) :

In immunocompetent children, molluscum contagiosum is entirely self-limiting, with spontaneous complete resolution typically occurring within 6 to 18 months (occasionally lasting up to 3 to 5 years).

Because active destructive therapies (cryotherapy, curettage) cause significant pain, emotional trauma in young children, and carry risks of permanent scarring or post-inflammatory hypopigmentation, observation, watchful waiting, and parental reassurance are strongly recommended as first-line management.

Counsel parents to avoid sharing towels or bath sponges, keep lesions covered with loose clothing or bandages during contact sports, and discourage picking or scratching to prevent autoinoculation.

Active Treatment Options (for symptomatic, cosmetically distressing, extensive, or sexually transmitted lesions):

Cantharidin (0.7% topical solution) : In-office application of a tiny droplet of cantharidin directly to the central umbilication using the blunt wooden end of a cotton-tipped applicator, avoiding surrounding normal skin. The area is washed off with soap and water after 2 to 6 hours. Cantharidin causes intraepidermal acantholysis and blistering, sloughing the molluscum body without scarring. Application is completely painless, making it well-suited for pediatric patients, though localized blistering and dyspigmentation occur.

Cryotherapy : Application of liquid nitrogen with a cotton swab or spray for 5 to 10 seconds per lesion until a 1-mm freeze halo appears. Highly effective, but painful and carries a risk of permanent post-inflammatory hypopigmentation (especially in darker skin types).

Curettage : Physical enucleation of the central core using a sharp dermal curette, preceded by topical lidocaine-prilocaine (EMLA) cream. Produces rapid immediate clearance, with a minor risk of pinpoint scarring.

Topical Chemical Agents : Potassium hydroxide 10% solution, podophyllotoxin, or FDA-approved Berdazimer 10.3% topical gel (a novel nitric oxide-releasing agent applied once daily for 12 weeks).

Adult Genital Molluscum : Patients presenting with genital or suprapubic lesions should undergo active treatment to prevent sexual transmission and must receive a comprehensive STI screening including serologic testing for HIV and syphilis, as well as nucleic acid amplification testing (NAAT) for Chlamydia trachomatis and Neisseria gonorrhoeae .

Loading diagram... Clinical Triage and Management Algorithm for Cutaneous Viral Infections