Allergic contact dermatitis to cow's hair

Area of Science:

• Dermatology
• Allergology
• Occupational Health

Background:

• Delayed hypersensitivity reactions can manifest as chronic skin conditions in occupational settings.
• Cow hair exposure is a potential, though less common, allergen in agricultural environments.

Observation:

• A 32-year-old female farmer presented with a 5-year history of hand and forearm lesions.
• Symptoms recurred upon entering the cowshed and resolved when she left the farm environment.

Findings:

• Patch testing revealed a positive reaction to cow hair, indicating a delayed-type allergy.
• The patient also showed positive reactions to cobalt chloride, nickel sulfate, and thimerosal.
• Prick tests for inhalant allergens and cow's milk, along with IgE levels, were negative.

Implications:

• Highlights cow hair as a potential occupational allergen causing allergic contact dermatitis.
• Suggests the importance of patch testing with specific environmental allergens in suspected occupational dermatoses.
• Underscores the need for thorough patient history and environmental assessment in diagnosing allergic skin conditions.