Contact urticaria from cobalt chloride.

Area of Science:

• Dermatology
• Toxicology
• Allergy and Immunology

Background:

• Cobalt chloride is utilized as a color indicator in provocative sweat testing.
• Contact urticaria is a skin reaction characterized by hives upon skin contact with an allergen or irritant.

Observation:

• A case study identified cobalt chloride as a potential contact urticant.
• The observed urticarial reaction to cobalt chloride was likely non-immunologic.

Findings:

• Vasoactive amines are implicated as a partial cause of cobalt chloride-induced urticaria.
• Diphenhydramine and compound 48-80 effectively blocked the reaction to cobalt chloride, suggesting a role for histamine and related mediators.

Implications:

• Cobalt chloride should be recognized as a contact urticant.
• Understanding the non-immunologic pathway of this reaction can inform clinical management and diagnostic approaches.
• Further research into the role of vasoactive amines in chemical-induced urticaria is warranted.