Drug additives contact dermatitis

The Australian Adverse Drug Reactions Advisory Committee received 11 reports of adverse reactions associated with echinacea use between July 1996 and September 1997. There were three reports of hepatitis three reports of asthma one rash one of rash, myalgia, and nausea one urticaria one anaphylaxis (the previously described case) and one of dizziness and tongue swelling. Echinacea was the only reported ingestant in five of the eight reports, resembling hypersensitivity. Onset of symptoms occurred within 24 h in two cases. There are two additional published case reports of echinacea-associated contact dermatitis and anaphylaxis (Mullins, 1998). 

Although topical phenothiazine antihistamine preparations such as promethazine hydrochloride (Phenergan) cream are no longer used in the United States, such topical antihistamine preparations are still widely used in Europe. Individuals who have become sensitized by such topical phenothiazine antihistamines often suffer a flare of the dermatitis when a phenothiazine antihistamine is taken, i.e., a systemic eczematous contact dermatitis. In addition, many individuals acquire allergic sensitization to various phenothiazine drugs which show cross-reactions with the phenothiazine antihistamines. Table 6 lists the phenothiazine antihistamine compounds. 

Contact dermatitis to additives in food and drugs has been described, but is rare (Fischer 1973). It is more common to additives used in topical medications and cosmetics (Wilkinson 1972). Here we are dealing with a lymphocyte-mediated allergy where sensitization of the patients occurs after repeated local contact of the skin with the chemical. 

Some examples of common additives are given which may be used as drugs themselves (such as benzoyl peroxide for acne), in the synthesis of drugs (dicyclohexyl carbodiimide) or as antioxidants in final products. Ethylene diamine is present in topical drugs and in aminophylline and is the allergen in the latter compound. Several cases of occupational contact dermatitis have been reported (Corazza et al. 

---