What is the recommended treatment for a patient presenting with viral hives?

Treatment of Viral Hives

For viral hives (acute urticaria), start with a second-generation non-sedating H1 antihistamine such as cetirizine 10 mg, fexofenadine 180 mg, or loratadine 10 mg once daily, and if symptoms persist after 2-4 weeks, escalate the dose up to 4 times the standard dose before considering additional therapies. 1, 2

First-Line Treatment Approach

• Begin with second-generation H1 antihistamines as the definitive first-line therapy, with preferred agents including cetirizine, desloratadine, fexofenadine, levocetirizine, loratadine, or mizolastine 1, 2, 3
• Cetirizine reaches maximum concentration fastest, making it the optimal choice when rapid symptom relief is needed in acute viral hives 1, 2, 3
• Offer patients at least two different non-sedating antihistamines to trial, as individual responses vary significantly 2, 3

Dose Escalation Strategy

• Start with standard dosing (e.g., cetirizine 10 mg once daily) 1, 2
• If symptoms persist after 2-4 weeks, increase the dose up to 4 times the standard dose (e.g., cetirizine 40 mg daily) before adding other therapies 1, 2, 3
• This dose escalation is common practice and considered safe, even though it exceeds manufacturer's licensed recommendations 4

When to Add Adjunctive Therapy

• For inadequate response to high-dose H1 antihistamines, consider adding H2 antihistamines (ranitidine or cimetidine) in combination 1, 3
• First-generation sedating antihistamines (hydroxyzine) may be added at night for additional symptom control and to aid sleep 1
• Avoid first-generation antihistamines as first-line therapy due to significant sedation and cognitive impairment without superior efficacy 3

Role of Corticosteroids: Critical Limitation

• Corticosteroids should be restricted to short courses (3-10 days) for severe acute urticaria only, never for chronic management 1, 2
• Corticosteroids have slow onset of action, work by inhibiting gene expression, and are ineffective for acute symptom relief 2
• Chronic use leads to cumulative toxicity that is dose and time dependent, outweighing any benefit 1, 2

Critical Distinction: Isolated Urticaria vs. Anaphylaxis

• Systemic hives with no organ involvement can be managed with antihistamines alone 4
• If hypotension, bronchospasm, laryngeal edema, or angioedema involving the airway are present, this is anaphylaxis requiring immediate intramuscular epinephrine 4, 1
• Grade I reactions (isolated skin/mucosal signs with generalized erythema or urticaria) do not require epinephrine 1
• Never use antihistamines or corticosteroids in place of epinephrine for anaphylaxis, as antihistamines take 30-120 minutes to reach peak plasma concentrations and lack vasoconstrictive, bronchodilatory, and mast cell stabilization properties 1, 2

Trigger Identification and Avoidance

• Identify and minimize aggravating factors including overheating, stress, alcohol, aspirin, NSAIDs, and codeine 1, 2, 3
• Avoid NSAIDs in aspirin-sensitive patients with urticaria 2, 3
• Cooling antipruritic lotions (calamine or 1% menthol in aqueous cream) can provide symptomatic relief 3

Special Population Adjustments

• In moderate renal impairment, avoid acrivastine and halve the dose of cetirizine, levocetirizine, and hydroxyzine 1, 2
• In significant hepatic impairment, avoid mizolastine and hydroxyzine 1, 2
• During pregnancy, avoid antihistamines if possible, especially during the first trimester; if necessary, choose chlorphenamine due to its long safety record 2

Expected Course and Prognosis

• Approximately 50% of patients with wheals alone will be clear by 6 months 1, 2, 3
• Over 40% of patients with urticaria show good response to antihistamines 4, 1
• Viral hives typically resolve spontaneously as the underlying viral infection clears 5

Common Pitfalls to Avoid

• Do not confuse isolated urticaria with perioperative or systemic anaphylaxis—always check for systemic symptoms (hypotension, bronchospasm, angioedema) before deciding on treatment 1
• Do not undertreate—the majority of patients with urticaria benefit from higher doses of antihistamines than initially prescribed 5
• Do not use topical crotamiton cream or capsaicin for viral hives, as evidence does not support their use 3