Urticaria
Urticaria: Excerpt from In A Page: Pediatric Signs and Symptoms
Drug-induced urticaria is the most common form of urticaria in children; anaphylaxis and hereditary angioedema are life-threatening conditions; remember ABCs of resuscitation (airway, breathing, circulation); best treatment is prevention; that is, avoidance of causative agents.
Differential Diagnosis
- Urticaria
–Epidemiology: Lifetime incidence 20%; most cases resolve within 48 hours; chronic
>6 weeks
–Pathophysiology: Hypersensitivity reaction: allergens (IgE-mediated, prior sensitization), complement, and other cytokines activate mast cells and basophils to release histamine (also kinins, prostaglandins, serotonin) with plasma extravasation; wheals/hives: dermis edema
–Triggers: Most cases are idiopathic
–IgE-mediated: Insects (bees, wasps, scorpions, spiders, jellyfish), foods (eggs, shellfish, tree nuts, peanuts, tomatoes), drugs (penicillins, cephalosporins, NSAIDs, barbiturates, amphetamines, insulin, blood products), pollen, danders, food additives
–Non-IgE-mediated: Infections (strep, EBV; hepatitis A, B, and C; adenovirus, enterovirus; fleas, mites), drugs (opiates, acetylsalicylic acid, local anesthetics), physical (exercise, cold/heat, UV light, water, pressure), contrast dyes, latex
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Chronic urticaria: Associated with collagen vascular diseases (SLE, cryoglobulinemia), inflammatory bowel disease, malignancy, thyroiditis, hyperthyroidism, Behçet disease, vasculitis
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Angioedema: 50% of urticaria cases; subcutaneous and mucous membrane edema
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Anaphylaxis (IgE-mediated)
–Most potent foods: Peanuts, fish
–Mortality: 100–500 deaths/year in U.S.
–Associated shock has a poor prognosis
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Hereditary angioedema
–High mortality
–Most cases are autosomal dominant
–C1 esterase inhibitor deficiency
–Recurrent episodes of edema (face, upper
airway, extremities)
–Triggers: Trauma, surgery
–Unresponsive to epinephrine, antihistamines
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Others: Erythema multiforme, mastocytosis, guttate psoriasis, flushing, cellulitis
Workup and Diagnosis
- History: Exposure to triggers, associated symptoms, symptoms of hypo-/hyperthyroidism, “feeling of impending doom” (anaphylaxis), history of atopy, family history of systemic diseases
- Physical exam
–Wheals/hives: Transient, elevated, erythematous, severely pruritic plaques, sudden onset; each wheal lasts 30 minutes to 3 hours, reappearing in other areas
–Papular uritcaria: 2–3 mm red papules surrounded by 10–20 mm wheals, most common in toddlers, due to fleas and mites (e.g., scabies)
–Physical urticaria: 10–20 mm erythematous macules with central wheal
–Angioedema: Edema of face, hands, feet, genitalia
–Anaphylaxis: Irritability, wheals, broncho- or laryngospasm (wheezing/stridor), angioedema, hypotension (late finding in children), vomiting, bloody diarrhea, mental status change; develops over minutes to hours; may develop DIC
–Hereditary angioedema: Nonpruritic edema
- Labs/studies
–Urticaria/anaphylaxis: IgE antibody skin test or radioallergosorbent test for IgE-mediated causes; culture, microscopy (ova and parasites)
–Angioedema: C1 esterase inhibitor, C3, C4
–Chronic urticaria: ANA, urinalysis, CBC, CRP, ESR, thyroid antibodies
Treatment
- Urticaria: Antihistamine; if nonresponsive to antihistamine or chronic uritcaria, then use corticosteroids
- Severe angioedema/anaphylaxis: ABCs of resuscitation
–Epinephrine: 1:1,000, 0.01 mg/kg SC (1:10,000 IV/IO if in shock), every 15 minutes up to three doses, maximum cumulative dose: 0.3 mg (child), 0.5 mg (adult)
–IV fluids if hypotension
–Nebulized Albuterol; antihistamine; corticosteroid (for
late phase)
–Observation: Mild, 2–4 hrs; severe, 12–24 hours
–Consult pediatric allergist
–Give patient EpiPen for self-administration
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Hereditary angioedema
–C1 esterase inhibitor concentrate; adults, danazol
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Avoid exposure to causative agents
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Desensitization to insect venoms
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Treat underlying disorders
Book Source Details
- Book Title: In A Page: Pediatric Signs and Symptoms
- Author(s): Jonathan E. Teitelbaum, Kathleen O. Deantonis, Scott Kahan
- Year of Publication: 2007
- Copyright Details: In A Page: Pediatric Signs and Symptoms, Copyright © 2007 Lippincott Williams & Wilkins.
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- "In A Page: Pediatric Signs and Symptoms" (2007)
- [ read ]
- Urticaria
- "A Pocket Manual of Differential Diagnosis" (1999)
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- Anaphylaxis
- "Professional Guide to Diseases (Eighth Edition)" (2005)
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- Urticaria
- "The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter" (2000)
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- Urticaria
- "Alarming Signs and Symptoms: Lippincott Manual of Nursing Practice Series" (2007)
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- Urticaria
- "Signs & Symptoms: A 2-in-1 Reference for Nurses" (2007)
- [ read ]
Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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More About This Book:
Title: In A Page: Pediatric Signs and Symptoms
Authors: Jonathan E. Teitelbaum, Kathleen O. Deantonis, Scott Kahan
Publisher: Lippincott Williams & Wilkins
Copyright: 2007
ISBN: 1-4051-0427-9
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» Next page: Urticaria [Hives] (Handbook of Signs & Symptoms (Third Edition))
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