Figure 7 – The pattern of erythema, vesiculation, and edema on this man's finger suggests allergic contact dermatitis. The suspected culprit was nickel in the ring he habitually wore.
IRRITANT CONTACT DERMATITIS
Clinical features. In elderly persons, irritant contact dermatitis is commonly caused by topical medications. It develops as a response to chemical damage to the epidermis and presents as an inflammation of the skin with varying degrees of erythema, edema, and scaling (Figure 6). Irritant contact dermatitis does not spread beyond the initial area of application.
In the United States, irritant contact dermatitis is common in persons who constantly expose their skin to water or other irritants, and it is seen more frequently in women, probably from exposure to cleaning products.4 Irritants such as detergents and solvents strip protective oils from the skin. Strong irritants produce immediate reactions, while mild irritants require longer exposure before a reaction develops. Initial symptoms include warmth, burning, and stinging.
Secondary infections can occur, particularly with Staphylococcus aureus. A skin biopsy can be done to exclude other disorders, such as psoriasis.
Treatment. Irritant contact dermatitis responds well to bland, topical corticosteroids, such as triamcinolone(Drug information on triamcinolone) 0.025% ointment in a pure petrolatum base. Ultimately, the only truly effective treatment is avoidance of the irritating substance.
ALLERGIC CONTACT DERMATITIS
Clinical features. Allergic contact dermatitis is characterized by erythema, edema, and vesiculation. This delayed type of induced sensitivity results from cutaneous contact with an allergen to which the patient has a specific sensitivity. The dermatitis occurs at sites where substances or metals have been applied (Figure 7). In elderly persons, the development of allergic contact dermatitis may be delayed somewhat, but the dermatitis may be more persistent once it occurs.5
Treatment. This involves identification of the allergen with patch testing and avoidance of it. Immediate symptoms can be treated with topical corticosteroids.
Patients with stasis dermatitis are at high risk for the development of allergic contact dermatitis to materials and agents applied to the areas of stasis dermatitis and leg ulcers. Neomycin(Drug information on neomycin) is an important cause of allergic contact dermatitis in these persons because it is used frequently despite the lack of documentation of its efficacy in the treatment of stasis ulcers.6