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Refractory cholinergic urticaria successfully treated with ketotifen
S P McClean1, E E Arreaza, M A Lett-Brown
1Department of Medicine, University of Texas Medical Branch, Galveston 77550.
The Journal of Allergy and Clinical Immunology
|April 1, 1989
Summary
Ketotifen effectively treated four patients with severe cholinergic urticaria (CU) refractory to antihistamines. This drug, acting as an H1 antagonist and mast cell stabilizer, improved symptoms and blocked histamine release during exercise challenges.
Area of Science:
- Dermatology
- Allergy and Immunology
Background:
- Cholinergic urticaria (CU) is a hypersensitivity reaction often triggered by heat, exercise, or emotional stress.
- Some patients experience severe symptoms, including cardiorespiratory manifestations, and may not respond to conventional treatments.
Observation:
- Four patients with severe CU, some triggered by cold, heat, and exercise, were studied.
- Exercise challenges revealed significant increases in plasma histamine levels (6- to 20-fold) preceding symptom onset.
- All patients were refractory to standard antihistamine therapy.
Findings:
- Ketotifen, administered at 3-8 mg/day, led to symptomatic improvement in all four patients.
- Repeat exercise challenges showed clinical improvement, with three patients exhibiting blocked mast cell mediator release and stable histamine levels.
- The fourth patient showed a partial reduction in histamine elevation.
Implications:
- Ketotifen demonstrates dual action as an H1 histamine-receptor antagonist and a mast cell stabilizer.
- These findings suggest ketotifen may be a more effective treatment option for severe, refractory cases of cholinergic urticaria compared to conventional antihistamines.
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