Sulfonamide allergy cross-reactions

Sulfonamides and phenothiazines are usually not intended for topical use, but accidental exposure occurs in hospital personnel and inpatients using the drugs orally. They can cause photocontact allergy, and cross-reactions between the related chemicals are seen. Related antihistamines (e. g., phenergan), used topically, may induce photoallergy. 

In a literature review of the epidemiology of PPD sensitization as determined by patch tests, the median prevalence among dermatitis patients was 4.3 % (Asia), 4 % (Europe), and 6.2 % (North America) [361]. A multicenter European comparative PPD sensitization study found that such sensitization occurred more frequently in Central and Southern Europe than in Scandinavian countries [362]. Occupational exposures account for only a small portion of PPD allergy cases [363, 364], and the predominant cause of PPD allergy is due to consumer exposure to hair dyes [365-367]. Some cases of PPD sensitization may be due to cross-reaction with benzocaine, A-isopropyl-A-phenyl-paraphenylenediamine, p-toluenediamine, and sulfonamides [361-363, 368, 369]. In PPD-sensitized individuals, clinically severe allergic reactions may occur with cosmetic hair dyeing [361]. 

Hypersensitivity reactions Hypersensitivity reactions may occur in patients with or without a history of allergy or bronchial asthma cross-sensitivity with sulfonamides may also occur. Refer to Management of Acute Hypersensitivity Reactions. 

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