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Allergies are nickel, fragrances, preservatives, rubber (gloves), hair dye, adhesives, topical medications such as antibiotics.

About

• Itchy skin condition caused by an allergic reaction

Aetiology

• Type IV, or delayed, hypersensitivity reaction.
• Sensitisation occurs on initial exposure to the allergen and "memory" T-cells proliferate in lymphoid tissue.
• Subsequent exposure to allergen induces activation of the T-lymphocytes and inflammatory response.
• Rash after 48-72 hours after exposure to the allergen.

Causes: Tiny quantities of an allergen can induce dermatitis.

• Hair dye contains substances
• Nickel allergy
• Acrylate allergy associated with nail cosmetics.
• Topical antibiotics

Occupations at risk

• Metal workers
• Hairdressers, beauticians
• Health care workers
• Cleaners, painters and florists.

Clinical

• Eczema of the wrist contact allergy to nickel watch bracelet
• Eczema of the lower leg when ankle strapping has been removed due to contact allergy to rosin in the adhesive plaster
• Hand dermatitis caused by rubber accelerator chemicals used in the manufacture of rubber gloves
• Itchy red face due to contact allergy with methylisothiazolinone, a preservative in wash-off hair products and baby wipes.

Differentials

• Irritant contact dermatitis: excess water, soaps, detergents, solvents, acids, alkalis, and friction. Those with atopic dermatitis are particularly sensitive.
• Contact urticaria, rash seen in minutes of exposure and fades away within minutes to hours. Often due to latex.
• Fungal infections

Investigations

• Skin biopsy if severe and Allergy testing

Management

• Identify allergen using comprehensive patch tests and history.
• Wear appropriate gloves to protect hands from touching materials to which the patient reacts.
• Emollient creams, Topical steroids
• Topical or oral antibiotics for secondary infection
• Severe: Oral steroids, usually short courses, for severe cases. Azathioprine, Ciclosporin or other immunosuppressive agents. Tacrolimus ointment and pimecrolimus cream are immune-modulating drugs that inhibit calcineurin and may prove helpful for allergic contact dermatitis.

References