What is the recommended management, including trigger avoidance and medication dosing, for acute and chronic urticaria in a child?

Management of Urticaria in Pediatrics

Second-generation H1 antihistamines are the cornerstone of treatment for both acute and chronic urticaria in children, with approximately 40% achieving adequate control on standard doses alone. 1, 2

Initial Clinical Assessment

Diagnosis is clinical—extensive laboratory workup is unnecessary for typical acute urticaria. 2, 3

Key diagnostic features to identify:

• Wheal duration: Ordinary urticaria wheals last 2-24 hours; physical urticaria typically <1 hour (except delayed pressure urticaria); wheals lasting >24 hours suggest urticarial vasculitis requiring skin biopsy 1, 2
• Trigger identification: Document recent viral infections (most common in acute pediatric urticaria), food exposures (nuts, fish, eggs, milk), drug ingestion, physical stimuli (heat, cold, pressure, exercise), or latex/chemical contact 2, 3, 4
• Associated symptoms: Presence of angioedema worsens prognosis—over 50% with combined wheals and angioedema have active disease beyond 5 years versus 50% clear by 6 months with wheals alone 1

When to Investigate Further

• Acute urticaria: No routine testing unless history suggests specific IgE-mediated allergy, then perform skin-prick testing or specific IgE (CAP) assays 2, 3
• Chronic urticaria (>6 weeks): Obtain complete blood count with differential, ESR or CRP, and thyroid autoantibodies with thyroid function tests 2, 4
• Suspected autoimmune urticaria: Consider autologous serum skin test (ASST) in experienced centers—approximately 30% of chronic urticaria cases have autoimmune etiology 1, 5

Pharmacologic Management Algorithm

First-Line: H1 Antihistamines

Start with a second-generation (nonsedating) H1 antihistamine at standard pediatric dose. 1, 2

• Cetirizine and loratadine are preferred agents for chronic urticaria based on efficacy data 6
• Verify age-specific dosing against product labeling—restrictions vary for children <12 years 2
• Cetirizine 0.25 mg/kg twice daily has demonstrated efficacy in preventing acute urticaria in high-risk toddlers with atopic dermatitis 7
• Avoid first-generation sedating antihistamines (chlorpheniramine, hydroxyzine) due to marked sedative and anticholinergic effects, though they remain effective if second-generation agents fail 5, 6

Second-Line: Dose Escalation and Combinations

If inadequate response after 2 weeks, increase the second-generation H1 antihistamine dose up to 4-fold above the manufacturer's licensed recommendation when benefits outweigh risks. 1

For resistant cases, add:

• H2 antihistamine (e.g., ranitidine, cimetidine) in combination with H1 blocker—particularly effective for symptomatic dermatographism 1, 6
• Sedating antihistamine at bedtime for nocturnal symptoms 1
• Leukotriene receptor antagonist (montelukast)—may benefit a small subgroup of chronic urticaria patients 1, 3

Third-Line: Corticosteroids (Short-Course Only)

Oral corticosteroids should be restricted to brief courses (lower than adult dose of 50 mg daily for 3 days) for severe acute urticaria or angioedema affecting the mouth. 1, 2

• Short courses can shorten episode duration 2, 3
• Avoid long-term corticosteroid use—reserve only for delayed pressure urticaria or urticarial vasculitis under specialist supervision 1

Fourth-Line: Immunomodulators

For disabling chronic autoimmune urticaria unresponsive to optimal antihistamine therapy, consider cyclosporine or tacrolimus. 1, 3

• Omalizumab is increasingly used off-license for refractory pediatric cases 5
• Reserve immunomodulating therapies for specialist-managed cases only 1

Trigger Avoidance and Adjunctive Measures

Identify and eliminate specific triggers when possible—this improves outcomes in >40% of cases. 1

Mandatory Avoidances

• NSAIDs and aspirin: Can trigger mast cell degranulation and worsen urticaria 2, 3
• Known allergens: Foods, latex, chemicals identified through history or testing 2, 3

Physical Trigger Management

• Avoid overheating, emotional stress, and alcohol exposure 2
• For physical urticarias, minimize specific provocative stimuli (cold, pressure, exercise, heat) 1, 4

Symptomatic Relief

• Topical cooling agents: Calamine lotion or 1% menthol in aqueous cream for itch relief 2

Emergency Management: Anaphylaxis and Laryngeal Angioedema

Laryngeal angioedema or anaphylaxis requires immediate intramuscular epinephrine. 2, 3

• Dosing for children 15-30 kg (typical 18-month-old): 150 µg epinephrine autoinjector 2
• Administer second dose if no significant improvement after first injection 2
• Add parenteral hydrocortisone as adjunct for severe laryngeal edema (delayed therapeutic effect) 2
• Prescribe home epinephrine autoinjector when history indicates risk of recurrent life-threatening attacks 2

Common Pitfalls to Avoid

• Do not perform extensive laboratory workups for typical acute urticaria—they add no clinical value 2, 3
• Do not use long-term oral corticosteroids routinely—they are reserved for specific severe cases only 1, 2
• Do not overlook urticarial vasculitis—wheals persisting >24 hours require skin biopsy for histologic confirmation 1, 2
• Do not assume all chronic urticaria is idiopathic—approximately 30% have autoimmune etiology and 20% have identifiable triggers 1, 3

Prognosis

• Acute urticaria: 50% of children with wheals alone clear by 6 months 1
• Chronic urticaria with angioedema: Poorer outlook—over 50% have active disease beyond 5 years 1
• Antihistamine response: 40-44% of hospitalized pediatric patients report good response to antihistamines 1, 2
• Many cases remain idiopathic despite thorough evaluation 2, 3