A 38-year-old woman twisted her right ankle and applied a Chinese medicine patch to relieve the pain. The following day the patient developed a severe contact dermatitis (CD) with many small vesicles (<5 mm) and bullae (>5 mm) (Figure 152-1). The erythema had a well-demarcated border and was traced by the doctor's pen. Cold compresses and a high-potency topical steroid were prescribed. When the patient showed little improvement, a 2-week course of oral prednisone was given, starting with 60 mg daily and tapering down to 5 mg daily. The patient responded rapidly and the CD fully resolved.1,2
Severe acute allergic contact dermatitis on the ankle of a woman after application of a Chinese topical medicine for a sprained ankle. (Reproduced with permission from Milgrom EC, Usatine RP, Tan RA, Spector SL. Practical Allergy. Philadelphia, PA: Elsevier; 2004.)
CD is a common inflammatory skin condition characterized by erythematous and pruritic skin lesions resulting from the contact of skin with a foreign substance. Irritant contact dermatitis (ICD) is caused by the non–immune-modulated irritation of the skin by a substance, resulting in a skin changes. Allergic contact dermatitis (ACD) is a delayed-type (type-IV) hypersensitivity reaction in which a foreign substance comes into contact with the skin and, upon reexposure, skin changes occur.3
Some of the most common types of CD are secondary to exposures to poison ivy, nickel, preservatives, and fragrances.4,5
Patch testing data indicate that the five most prevalent contact allergens of more than 3700 known are nickel (20.1% of patients tested), fragrance mix (11.9%), the preservative methylisothiazolinone (MI) (10.9%), neomycin (8.4%), and a three-way tie (7.4%) between bacitracin, cobalt, and balsam of Peru.6
Occupational skin diseases (chiefly CD) rank second only to traumatic injuries as the most common type of occupational disease. Chemical irritants such as solvents and cutting fluids account for most ICD cases. In occupational skin diseases, 80% of the cases are related to ICD.5 Hands were primarily affected in 64% of ACD and 80% of ICD4 (Figure 152-2).
Occupational irritant contact dermatitis in a woman whose hands are exposed to onions while cooking in her family restaurant. (Reproduced with permission from Richard P. Usatine, MD.)
ETIOLOGY AND PATHOPHYSIOLOGY
CD is a common inflammatory skin condition characterized by erythematous and pruritic skin lesions resulting from the contact of skin with a foreign substance.
ICD is caused by the non–immune-modulated irritation of the skin by a substance, resulting in a skin rash.
ACD is a delayed-type hypersensitivity reaction in which a foreign substance comes into contact with the skin ...