31.1 Allergic Rhinitis & Acute Non-Anaphylactic Allergic Reactions

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

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

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4 Chapter 4: Lifestyle Counseling & Behavior Change

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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

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10 Chapter 10: Adult Cancer Screening: Breast & Gynecologic

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

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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

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

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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

31.1 Allergic Rhinitis & Acute Non-Anaphylactic Allergic Reactions

Key Takeaways Explain This Topic AI

Intranasal corticosteroids (INCS; fluticasone propionate, mometasone furoate) represent the single most effective first-line monotherapy for allergic rhinitis, significantly outperforming oral antihistamines across all nasal symptoms including congestion; consistent daily dosing is required for maximal efficacy.

Proper INCS administration technique requires tilting the head slightly forward and directing the spray nozzle laterally toward the ipsilateral ear (away from the nasal septum) to prevent epistaxis and avoid septal perforation.

Second-generation oral antihistamines (cetirizine, fexofenadine, loratadine) are non-sedating, lack anticholinergic side effects, and are preferred over first-generation agents (diphenhydramine, hydroxyzine); combining an INCS with an intranasal antihistamine (fluticasone + azelastine) offers superior, rapid-onset efficacy for moderate-to-severe symptoms.

Montelukast carries an FDA boxed warning for serious neuropsychiatric adverse events (depression, suicidality, sleep disturbances) and should strictly be reserved for allergic rhinitis with concurrent asthma or when first-line therapies are poorly tolerated.

Acute urticaria without anaphylaxis presents with pruritic, blanching, fleeting wheals (<24 hours per individual lesion) and is primarily managed with second-generation H1-antihistamines (which can be titrated up to 4 times the standard daily dose), reserving a short course of oral corticosteroids (prednisone 3-5 days) only for severe acute distress.

Last updated: September 2026

Allergic Rhinitis: Pathophysiology, Clinical Features & Diagnostic Assessment

Allergic rhinitis is a chronic inflammatory disorder of the nasal mucosa induced by an immunoglobulin E (IgE)-mediated hypersensitivity reaction following allergen exposure. It affects approximately 10% to 30% of adults and up to 40% of children globally, presenting significant morbidity, sleep disturbance, impairment of academic or occupational performance, and exacerbation of comorbid conditions including asthma, rhinosinusitis, and otitis media.

Immunologic Pathophysiology

Allergic rhinitis exemplifies a classic Gell and Coombs Type I (immediate-type) hypersensitivity reaction , progressing through three distinct phases:

Sensitization Phase :

Inhaled aeroallergens penetrate the nasal epithelial barrier and are captured, processed, and presented by local dendritic cells (antigen-presenting cells) via major histocompatibility complex (MHC) class II molecules to naive CD4+ T helper cells.

In genetically susceptible atopic individuals, naive T cells differentiate into Th2 helper lymphocytes under the influence of interleukin-4 (IL-4).

Activated Th2 cells secrete a characteristic cytokine profile:

IL-4 and IL-13 : Drive B-cell immunoglobulin class switching to synthesize allergen-specific IgE antibodies.

IL-5 : Promotes eosinophil differentiation, maturation, bone marrow release, and survival.

Allergen-specific IgE binds with high affinity to Fc-epsilon-RI (FcεRI) receptors located on the surface of mucosal mast cells and circulating basophils, leaving the mucosa primed and sensitized.

Early-Phase Reaction (Minutes) :

Upon subsequent re-exposure to the specific aeroallergen, multivalent allergen molecules cross-link adjacent IgE antibodies bound to FcεRI on sensitized mast cells.

Cross-linking triggers rapid intracellular calcium influx, cytoskeletal rearrangement, and immediate mast cell degranulation within 5 to 15 minutes.

Pre-formed and rapidly synthesized inflammatory mediators are released:

Histamine : Stimulates sensory H1 receptors on trigeminal unmyelinated C-fibers, triggering the sneeze reflex and intense mucosal pruritus. Histamine also stimulates H1 and H2 receptors on mucosal capillaries and post-capillary venules, inducing endothelial cell contraction, increased vascular permeability, plasma exudation, and profound mucosal edema.

Prostaglandin D2 (PGD2) & Cysteinyl Leukotrienes (LTC4, LTD4, LTE4) : Potent vasodilators that dramatically increase nasal airway resistance and stimulate seromucous glands to produce copious watery secretions ( rhinorrhea ).

Tryptase and neutral proteases : Cleave extracellular matrix and amplify local neurogenic inflammation.

Late-Phase Reaction (4 to 8 Hours Post-Exposure) :

Cytokines (IL-4, IL-5, IL-13, TNF-alpha) and chemokines (eotaxin/CCL11, RANTES/CCL5) synthesized during the early phase recruit inflammatory leukocytes into the nasal submucosa, predominantly eosinophils, basophils, neutrophils, and Th2 lymphocytes .

Recruited eosinophils degranulate, discharging cytotoxic basic proteins: major basic protein (MBP), eosinophil cationic protein (ECP), and eosinophil peroxidase (EPO) .

These cytotoxic granule proteins cause nasal epithelial desquamation, mucosal hyperresponsiveness to nonspecific irritants (such as tobacco smoke, cold air, and strong perfumes), and persistent tissue inflammation.

Nasal congestion (airway obstruction) is the dominant clinical hallmark of the late-phase reaction due to sustained venous pooling in the cavernous sinusoids of the inferior turbinates and prolonged submucosal interstitial edema. IMMUNOLOGIC CASCADE OF ALLERGIC RHINITIS

• Aeroallergen Exposure
• │
• ▼
• Dendritic Cell Antigen Presentation ──> Th2 Differentiation (IL-4)
• │ │
• │ ├─> IL-4 / IL-13 ──> B-cell IgE Synthesis
• │ └─> IL-5 ─────────> Eosinophil Activation
• ▼
• Sensitization: IgE binds FcεRI on Mast Cells
• │
• [Re-exposure]
• ▼
• Allergen Cross-links IgE ──> Degranulation (5-15 min)
• │
• ├─> EARLY PHASE: Histamine, PGD2, LTC4/D4
• │ • Sneezing (trigeminal stimulation)
• │ • Pruritus (palate, nose, eyes)
• │ • Watery rhinorrhea (glandular hypersecretion)
• │
• └─> LATE PHASE (4-8 hours): Eosinophil / Th2 Infiltration
• Cytotoxic proteins (MBP, ECP)
• Submucosal venous pooling & sustained edema
• Severe nasal congestion & mucosal hyperresponsiveness
• Aeroallergen Classification: Seasonal vs. Perennial

Accurate identification of aeroallergen triggers guides environmental avoidance and pharmacotherapy scheduling:

Classification Dominant Aeroallergens Peak Seasonal Timing Typical Clinical Presentation

Seasonal Allergic Rhinitis (Hay Fever) • Tree pollen (Oak, Birch, Cedar, Maple); • Grass pollen (Timothy, Kentucky Bluegrass, Bermuda); • Weed pollen (Ragweed [ Ambrosia ], Pigweed, Sagebrush) • Trees: Early Spring (March-May); • Grasses: Late Spring to Mid-Summer (May-July); • Weeds: Late Summer to First Frost (August-October) Episodic, paroxysmal sneezing bursts, intense ocular and palatal pruritus, clear profuse rhinorrhea, conjunctival injection. Symptoms closely track environmental pollen counts.

Perennial Allergic Rhinitis • House dust mites ( Dermatophagoides pteronyssinus , D. farinae ); • Domestic animal dander (Cat Fel d 1 , Dog Can f 1 ); • Pest allergens (German cockroach Bla g 1/2 , rodents); • Indoor molds ( Aspergillus , Penicillium , Alternaria ) Year-round chronic exposure; frequently worsens in winter due to closed indoor environments and forced-air heating Chronic bilateral nasal congestion, persistent postnasal drip, nocturnal mouth breathing, dry throat upon waking, frequent throat clearing, chronic cough. Sneezing and pruritus are often less prominent than in seasonal disease.

Clinical Presentation & Physical Examination Findings

Diagnosis of allergic rhinitis is clinical, established by a compatible history of allergen-induced symptoms supported by targeted physical examination findings.

History and Cardinal Symptoms

Paroxysmal Sneezing : Typically occurring in bursts of 5 to 10 sneezes upon waking or immediately upon allergen encounter.

Clear Anterior and Posterior Rhinorrhea : Thin, watery, non-purulent secretions. Posterior drainage triggers a scratchy throat, frequent throat-clearing, and a dry nocturnal cough.

Nasal Congestion / Obstruction : Bilateral or alternating nasal blockage, leading to habitual mouth breathing, snoring, sleep fragmentation, daytime fatigue, and hyposmia.

Pruritus : Itching localized to the nasal tip, hard and soft palate, pharynx, and inner ears (via the Eustachian tube and tympanic plexus innervation).

Ocular Symptoms (Allergic Rhinoconjunctivitis) : Bilateral conjunctival erythema, tearing, chemosis (conjunctival edema), and severe periorbital pruritus.

Classic Physical Examination Stigmata

Careful head and neck examination reveals hallmark phenotypic signs of chronic atopic disease:

Allergic Shiners : Symmetric, dark, bluish-purple hyperpigmentation under both lower eyelids. Caused by chronic venous stasis and venous pooling in the ethmoidal and infraorbital venous plexuses secondary to obstructed, swollen nasal turbinates.

Dennie-Morgan Lines (Infraorbital Folds) : Prominent transverse skin folds or creases beneath the margin of the lower eyelids, arising from recurrent eyelid edema and continuous spasm of the superior tarsal muscle.

Allergic Salute & Transverse Nasal Crease : The "allergic salute" is the characteristic repetitive upward wiping or pushing of the nasal tip with the open palm to relieve itching and transiently dilate the anterior nasal valve. Over months to years, this upward mechanical pressure produces a permanent horizontal, hypopigmented or hyperpigmented line across the lower third of the nasal bridge—the transverse nasal crease .

Allergic Gaping : Chronic mouth breathing resulting in an open-mouthed facial posture, dry chapped lips, and in children, altered dentofacial growth (high-arched palate, dental malocclusion).

Posterior Pharyngeal Cobblestoning : Hypertrophy of lymphoid tissue along the posterior pharyngeal wall resembling cobblestones, driven by chronic postnasal drip and localized lymphoid follicular hyperplasia.

Anterior Rhinoscopy: Allergic vs. Non-Allergic Turbinates

Inspection of the nasal cavity using an otoscope with a wide speculum or nasal speculum is mandatory to distinguish allergic rhinitis from infectious and drug-induced etiologies: TURBINATE APPEARANCE: ALLERGIC vs. INFECTIOUS vs. MEDICAMENTOSA

• [Allergic Rhinitis] [Viral Rhinosinusitis] [Rhinitis Medicamentosa]
• Pale, boggy, bluish-gray • Beefy, erythematous, red • Fiery red, swollen mucosa
• Edematous turbinates • Swollen turbinates • Punctate submucosal bleeding
• Copious clear, watery mucus • Clear to mucopurulent mucus • History of oxymetazoline >3-5 d

Allergic Rhinitis : Nasal mucosa and inferior turbinates are characteristically swollen, edematous, boggy, and pale or bluish-gray (violaceous) in coloration, bathed in thin, clear, watery secretions.

Infectious (Viral) Rhinitis : Nasal mucosa is erythematous, hyperemic, and beefy red , often with thick, cloudy, or mucopurulent discharge.

Rhinitis Medicamentosa : Severely swollen, fiery red, hyperemic mucosa with punctate bleeding sites , accompanied by a history of topical decongestant spray overuse (e.g., oxymetazoline or phenylephrine) exceeding 3 to 5 consecutive days.

Evidence-Based Pharmacotherapy for Allergic Rhinitis

The American Academy of Otolaryngology–Head and Neck Surgery (AAO-HNS) and the Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines delineate a clear hierarchy of pharmacologic interventions based on symptom severity and chronicity.

Pharmacologic Class Comparison

Drug Class Examples & Dosages Primary Mechanism Efficacy on Cardinal Symptoms Clinical Pearls & Adverse Effects

Intranasal Corticosteroids (INCS) • Fluticasone propionate (50 mcg/spray; 1-2 sprays/nostril daily); • Mometasone furoate (50 mcg/spray; 1-2 sprays/nostril daily); • Budesonide (32 mcg/spray; 1-2 sprays/nostril daily) Suppresses cytokine gene transcription, inhibits eosinophil and mast cell recruitment, decreases mucosal edema Most effective monotherapy across all symptoms : sneezing, rhinorrhea, pruritus, AND congestion First-line choice. Requires regular daily use (onset 6-12h, peak 1-2 weeks). Epistaxis risk if sprayed onto septum.

Second-Generation Oral Antihistamines • Cetirizine (10 mg daily); • Fexofenadine (180 mg daily); • Loratadine (10 mg daily); • Levocetirizine (5 mg daily) Selective peripheral H1-receptor inverse agonism; minimal CNS penetration Excellent for sneezing, itching, and rhinorrhea; poor efficacy for nasal congestion Non-sedating (fexofenadine is zero-sedation; cetirizine has mild ~10% sedation). Lack anticholinergic toxicity of first-generation agents.

Intranasal Antihistamines • Azelastine 0.1% or 0.15% (1-2 sprays/nostril BID); • Olopatadine 0.6% (2 sprays/nostril BID) Topically blocks mucosal H1 receptors; downregulates mast cell mediator release Rapid relief of sneezing, itching, rhinorrhea, and moderate relief of congestion Rapid onset (<15 minutes) . Useful on-demand or as add-on. Main side effect: bitter taste (dysgeusia), somnolence in ~5%.

Combination INCS + Intranasal Antihistamine • Azelastine / Fluticasone propionate (137 mcg / 50 mcg per spray; 1 spray/nostril BID) Simultaneous mucosal corticosteroid anti-inflammatory action + rapid H1 receptor blockade Superior overall symptom control compared to either monotherapy alone First-line for moderate-to-severe allergic rhinitis or patients who fail initial monotherapy. Rapid onset within 15-30 min.

Leukotriene Receptor Antagonists (LTRA) • Montelukast (10 mg PO daily at bedtime) Selective competitive antagonism of the cysteinyl leukotriene-1 (CysLT1) receptor Modest relief of rhinorrhea, sneezing, and congestion; less effective than INCS FDA Boxed Warning (Black Box) for serious neuropsychiatric events. Reserve strictly for allergic rhinitis with concurrent asthma.

Oral Decongestants • Pseudoephedrine (30-60 mg q4-6h or 120 mg ER BID); • Phenylephrine (ineffective orally due to extensive first-pass metabolism) Direct and indirect alpha-1 adrenergic agonism causing mucosal arteriolar constriction Highly effective for nasal congestion only; zero effect on sneezing, itching, or rhinorrhea Adverse effects: hypertension, tachycardia, palpitations, insomnia, tremor, acute urinary retention in BPH. Contraindicated in uncontrolled HTN.

Topical Nasal Decongestants • Oxymetazoline 0.05% (2-3 sprays/nostril q12h); • Phenylephrine 0.5% Potent direct alpha-1 and alpha-2 adrenergic vasoconstriction of capacitance venules Dramatic, immediate relief of severe congestion within 1-5 minutes Strictly limit use to ≤3 to 5 consecutive days to prevent rhinitis medicamentosa (rebound mucosal hyperreactivity and tachyphylaxis).

Intranasal Mast Cell Stabilizers • Cromolyn sodium 5.2 mg/spray (1 spray/nostril 3-4 times daily) Inhibits mast cell calcium influx, blocking early and late phase degranulation Mild-to-moderate relief of sneezing, rhinorrhea, and itching; weak for congestion Excellent safety profile (pregnancy category B). Frequent dosing (QID) limits adherence. Must be started 1-2 weeks prior to exposure.

Intranasal Corticosteroids (INCS): The Gold Standard Monotherapy

Intranasal corticosteroids are the most potent and effective pharmacologic class for allergic rhinitis. Systematic reviews and clinical trials consistently demonstrate their superiority over oral antihistamines and leukotriene receptor antagonists for relieving all four cardinal symptoms, particularly nasal congestion .

Crucial Patient Counseling: Administration Technique

Improper administration is the leading reason for treatment failure and local adverse effects (epistaxis and septal perforation):

Clear Nasal Passages First : Gently blow the nose or perform saline nasal irrigation to clear excess mucus prior to dosing.

Head Position : Tilt the head slightly downward (chin tucked toward the chest), looking at the floor, rather than throwing the head backward (which causes the medication to drain into the throat, causing an unpleasant taste and systemic absorption).

Contralateral Hand Technique : Hold the spray bottle in the right hand to spray the left nostril, and in the left hand to spray the right nostril.

Spray Away from the Septum : Direct the nozzle laterally toward the outer corner of the ipsilateral eye or the ipsilateral ear tragus . Never direct the spray medially toward the nasal septum.

Why? Directing corticosteroid spray onto the anterior nasal septum (Kiesselbach's plexus) causes mucosal atrophy, chronic crusting, recurrent epistaxis, and rarely, full-thickness nasal septal perforation .

Gentle Inspiration : Breathe in gently through the nose as the spray is actuated; avoid vigorous sniffing, which draws the drug straight into the pharynx. CORRECT INTRANASAL CORTICOSTEROID DELIVERY TECHNIQUE

[Right Hand Sprays Left Nostril]

• Forehead
• │
• ▼
• Left Eye ◄─────── Nozzle Aimed Laterally
• │ (Toward Ipsilateral Ear / Outer Eye)
• ▼
• Nasal Septum [AVOID DIRECT CONTACT!]
• │ (Prevents Epistaxis & Septal Perforation)
• ▼
• Chin Down
• Second-Generation Oral Antihistamines: Why First-Generation Agents Are Deprecated

Oral H1-antihistamines act as inverse agonists, stabilizing the inactive conformation of H1 receptors. Second-generation agents (cetirizine, fexofenadine, loratadine, desloratadine, levocetirizine) are standard of care:

Lipophobicity and High Molecular Weight : Unlike first-generation compounds (diphenhydramine, hydroxyzine, chlorpheniramine), second-generation antihistamines do not readily cross the blood-brain barrier.

Absence of Central Anticholinergic Side Effects : First-generation antihistamines block muscarinic, alpha-adrenergic, and serotonergic receptors, resulting in daytime sedation, cognitive blunting, dry mouth, blurred vision, constipation, urinary retention, and increased fall risk in elderly individuals. In children, they may cause paradoxical excitation.

Fexofenadine Pearl : Completely non-sedating even at supratherapeutic doses because it is an active P-glycoprotein substrate excluded from the CNS. Must not be taken with fruit juices (grapefruit, orange, apple), which inhibit intestinal organic anion transporting polypeptide (OATP1A2), reducing fexofenadine bioavailability by up to 70%.

Cetirizine Pearl : Fast onset of action (within 1 hour), but produces mild somnolence in approximately 10% of patients; best taken in the evening.

Montelukast FDA Boxed Warning: Clear Clinical Indications

In March 2020, the U.S. FDA issued a Boxed Warning (Black Box) for montelukast regarding the risk of serious neuropsychiatric events :

Reported events include: dream abnormalities, insomnia, anxiety, depression, agitation, aggressive behavior, hallucinations, and suicidal ideation and completed suicide .

Guideline Mandate : Montelukast should NOT be prescribed as first-line or routine therapy for mild-to-moderate allergic rhinitis.

Appropriate Clinical Indications : Reserve montelukast exclusively for patients who have an inadequate response or intolerance to INCS and oral antihistamines, OR for patients with allergic rhinitis with comorbid mild persistent asthma , where a single oral medication can target both upper and lower airway cysteinyl leukotriene-mediated inflammation.

Allergen-Specific Immunotherapy (AIT): Disease Modification

Allergen immunotherapy is the only treatment modality that alters the natural history and underlying immunology of allergic rhinitis .

Indications : Patients with confirmed IgE-mediated allergy (via skin prick testing or serum allergen-specific IgE) who have severe, persistent symptoms despite optimal pharmacotherapy, those intolerant of medications, or those wishing to avoid long-term drug use. AIT also prevents the subsequent development of allergic asthma in children with allergic rhinitis.

Modalities :

Subcutaneous Immunotherapy (SCIT) : Weekly incremental allergen injections during the build-up phase (3-6 months), followed by monthly maintenance injections for 3 to 5 years . Carries a small risk of systemic anaphylaxis; must be administered in a clinic equipped with emergency resuscitation gear and observed for 30 minutes.

Sublingual Immunotherapy (SLIT) : Daily dissolvable oral tablets (FDA-approved for timothy grass, ragweed, and dust mites). First dose administered under medical supervision; subsequent doses self-administered at home. First-line home treatment requires an auto-injectable epinephrine prescription.

Mechanism : Induces regulatory T cells (Tregs) , secretes IL-10 and TGF-beta, suppresses Th2 responses, shifts antibody production from IgE to allergen-specific blocking IgG4 , and diminishes tissue mast cell and basophil sensitivity.

Acute Non-Anaphylactic Allergic Reactions: Acute Urticaria & Angioedema

Acute urticaria is defined by the sudden appearance of urticarial lesions (wheals) , angioedema, or both, lasting less than 6 weeks in total duration.

Pathophysiology & Clinical Features

The Wheal : A circumscribed, raised, erythematous lesion with a pale, swollen center, surrounded by an erythematous flare. It is accompanied by intense pruritus and is blanchable upon compression.

Fleeting / Transient Nature : The hallmark distinguishing feature of urticaria is that individual lesions appear, evolve, and resolve completely within 24 hours (typically 2 to 12 hours) without leaving residual bruising, scaling, or hyperpigmentation.

Clinical Pearl / Diagnostic Red Flag : If individual lesions persist in the exact same location for >24 hours , are tender or burning rather than pruritic, and resolve with residual petechiae, ecchymosis, or post-inflammatory hyperpigmentation, the clinician must suspect urticarial vasculitis and obtain a skin punch biopsy.

Angioedema : Involves mast cell degranulation in the deeper dermis, subcutaneous tissue, or submucosa. It produces non-pitting, non-pruritic, painful or burning swelling of the lips, eyelids, tongue, genitalia, or extremities, resolving more slowly over 48 to 72 hours.

Mandatory Triage: Ruling Out Anaphylaxis

Whenever an acute allergic reaction or urticaria presents, the clinician must immediately evaluate for life-threatening anaphylaxis :

Respiratory : Laryngeal stridor, hoarseness, sensation of throat tightness, wheezing, dyspnea, persistent cough, SpO2 <92%.

Cardiovascular : Hypotension (systolic BP <90 mmHg or >30% drop from baseline), diaphoresis, lightheadedness, syncope, tachycardia.

Gastrointestinal : Severe crampy abdominal pain, repetitive projectile vomiting, diarrhea.

Action : If any airway, respiratory, or circulatory compromise is present, administer Intramuscular Epinephrine (0.3 to 0.5 mg of 1:1,000 [1 mg/mL] solution into the mid-anterolateral thigh) immediately, activate EMS, and place the patient in the recumbent position with legs elevated.

Stepwise Management of Acute Non-Anaphylactic Urticaria

For isolated acute urticaria without respiratory compromise or hemodynamic collapse:

First-Line: Second-Generation H1-Antihistamines :

Initiate a modern second-generation oral H1-antihistamine (cetirizine 10 mg daily, fexofenadine 180 mg daily, or bilastine 20 mg daily).

Dose Up-Titration : International urticaria guidelines (EAACI/GA2LEN/WAO) strongly recommend that if symptoms persist at standard doses, the clinician should up-titrate the second-generation antihistamine up to 4 times the standard daily dose (e.g., cetirizine 20 mg BID or 40 mg daily; fexofenadine 180 mg BID or 360 mg daily) before adding secondary agents.

Second-Line Add-On: H2-Receptor Antagonists :

Cutaneous microvasculature possesses both H1 (85%) and H2 (15%) receptors. Adding famotidine (20 mg PO twice daily) can provide synergistic relief in patients unresponsive to high-dose H1 blockade.

Severe Acute Discomfort: Short-Course Systemic Corticosteroids :

For patients with severe, extensive, sleep-disrupting urticaria or significant facial angioedema, prescribe a short oral corticosteroid burst: Prednisone 40 mg PO daily for 3 to 5 days .

Prolonged courses or tapers are unnecessary for acute urticaria and carry substantial metabolic and bone toxicity risks. Long-term steroids are strictly avoided.

Avoid Triggers : Discontinue potential drug culprits (NSAIDs, ACE inhibitors, new antibiotics) and avoid alcohol, heat, tight clothing, and vigorous exercise during the acute flare.

Loading diagram... Stepwise Management of Allergic Rhinitis & Acute Urticaria