Combined cold- and heat-induced cholinergic urticaria

Area of Science:

• Dermatology
• Allergy and Immunology

Background:

• Physical urticaria encompasses conditions triggered by physical stimuli like temperature and exercise.
• Cholinergic urticaria is a common form, characterized by small wheals induced by heat or exercise.

Observation:

• A 36-year-old woman presented with a 20-year history of symptoms triggered by physical activity, heat, and cold.
• Positive methacholine skin test and wheal formation upon cold and warm water immersion, and exercise.
• Symptoms included cutaneous lesions, lightheadedness, and severe asthma.

Findings:

• Cold and heat challenges induced urticarial lesions and increased plasma histamine levels.
• Exercise also triggered urticarial lesions.
• Combined H1 and H2 antihistamine therapy markedly reduced symptoms but did not eliminate histamine release.

Implications:

• This case highlights the complex interplay of physical factors in urticaria.
• Antihistamine therapy is effective, but underlying histamine release mechanisms may persist.
• Further research into the pathophysiology of physical urticaria is warranted.