From the Guidelines
For heat-induced urticaria, the most effective treatment is to start with over-the-counter antihistamines like cetirizine (Zyrtec) or fexofenadine (Allegra), taking 10mg daily, as they are the mainstay of therapy and can provide relief within an hour 1. To manage heat-induced hives, it is essential to take a multi-faceted approach, including:
- Applying a cool, damp cloth to affected areas and taking a cool shower to constrict blood vessels and reduce inflammation
- Wearing loose, breathable clothing and staying in air-conditioned environments when possible to avoid triggers
- Avoiding scratching to prevent further irritation If symptoms persist, consulting a doctor for prescription options like higher-strength antihistamines or corticosteroids, such as prednisolone 50 mg daily for 3 days in adults, may be necessary 1. Antihistamines work by blocking histamine receptors, reducing the immune system's overreaction to heat that causes hives. Long-term management focuses on avoiding triggers and maintaining a consistent antihistamine presence in your system to prevent outbreaks. It is crucial to note that while corticosteroids may be effective in shortening the duration of acute urticaria, long-term oral corticosteroids should not be used in chronic urticaria except in very selected cases under regular specialist supervision 1.
From the Research
Treatment Options for Heat-Induced Urticaria
- The treatment of heat-induced urticaria typically involves the use of nonsedating H1 antihistamines, which are effective in nearly 60% of patients, although full symptom relief is achieved in only a minority of them 2.
- A heat desensitization programme can be an effective treatment for heat-induced urticaria 2.
- Omalizumab has proven effective in recent case reports for the treatment of heat-induced urticaria 2.
- Second-generation, relatively non-sedating H₁-receptor blockers are typically employed up to 4 times a day for the treatment of chronic spontaneous urticaria, which may also be effective for heat-induced urticaria 3.
- Increasing the dosage of levocetirizine and desloratadine up to 4-fold may improve symptoms of chronic urticaria, including heat-induced urticaria, without compromising safety in approximately three quarters of patients with difficult-to-treat chronic urticaria 4.
Antihistamine Therapy
- Low-sedating H1 antihistamines, such as terfenadine, astemizole, loratadine, and cetirizine, are effective for the treatment of urticaria and angioedema, including heat-induced urticaria, with reduced sedative and anticholinergic side effects 5, 6.
- The choice of a particular low-sedating H1 antihistamine depends on pharmacokinetic considerations and frequency of administration 6.
Other Treatment Considerations
- Corticosteroids should not be employed chronically due to cumulative toxicity that is dose and time dependent, but brief courses of steroid can be employed for severe exacerbations of urticaria, including heat-induced urticaria 3.
- Cyclosporine is recommended for patients who are unresponsive to both antihistamines and omalizumab, and is similarly effective in 65%-70% of patients, although care is needed regarding possible side-effects on blood pressure and renal function 3.