Management of Heat Urticaria

First-Line Treatment

The American Academy of Allergy, Asthma, and Immunology recommends second-generation non-sedating H1 antihistamines as the mainstay of therapy for heat urticaria, with options including cetirizine, desloratadine, fexofenadine, levocetirizine, loratadine, and mizolastine 3, 2
Patients should be offered at least two different non-sedating antihistamines, as responses and tolerance vary between individuals 4, 2
For inadequate symptom control after 2-4 weeks, the dose can be increased up to 4 times the standard dose 1, 2
Cetirizine has the shortest time to attain maximum concentration, which may be advantageous when rapid relief is needed for acute symptoms 4

For urticaria unresponsive to high-dose antihistamines, the British Society for Allergy and Clinical Immunology recommends adding omalizumab at a standard starting dose of 300 mg every 4 weeks 1, 2
The dose can be increased up to 600 mg every 2 weeks in patients with insufficient response 2
Allow up to 6 months for patients to respond to omalizumab before considering alternative treatments 1, 2

For patients who do not respond to high-dose antihistamines and omalizumab within 6 months, the American Academy of Allergy, Asthma, and Immunology recommends adding cyclosporine to the antihistamine regimen 1, 2
Cyclosporine is effective in about 65-70% of patients at a dose of up to 5 mg/kg body weight 1
Regular monitoring of blood pressure and renal function is required due to potential side effects 2, 5

Identify and minimize aggravating factors such as overheating, stress, alcohol, and certain medications (aspirin, NSAIDs, codeine) 4, 2
NSAIDs should be avoided in aspirin-sensitive patients with urticaria 4, 5
Cooling antipruritic lotions (calamine or 1% menthol in aqueous cream) can provide symptomatic relief 4, 5
Patient education about the generally favorable prognosis for eventual recovery is important 4, 2

Oral corticosteroids should be restricted to short courses (3-10 days) for severe acute exacerbations but should not be used chronically due to cumulative toxicity 3
First-generation antihistamines may be added at night for additional symptom control, but their sedating effects should be considered 6

Start with standard dose of second-generation H1 antihistamine 1, 2
If inadequate control after 2-4 weeks, increase dose up to 4 times the standard dose 1, 2
If still inadequate control, add omalizumab 300 mg every 4 weeks (can increase to 600 mg every 2 weeks if needed) 1, 2
If inadequate response to omalizumab within 6 months, add cyclosporine (up to 5 mg/kg body weight) 1, 2