title: Systemic contact dermatitis to hydroxyzine.
abstract: Systemic contact dermatitis is an underreported type of delayed hypersensitivity caused by a systemically administered substance. When interpreting patch test reactions, it is important to obtain a history of all current related oral medications. Many oral medications can cross-react with structurally similar topical antigens and induce systemic contact dermatitis. Identification and elimination of the inciting agent can lead to resolution of otherwise chronic, unresponsive eczema. We report a case of systemic contact dermatitis to hydroxyzine in a patient who was patch tested positive to ethylenediamine. Repeated oral provocation with hydroxyzine reproduced her eczema on several occasions. We conclude that systemic contact dermatitis to hydroxyzine, a common medication used to treat pruritus, must be considered as a potential cause for unresponsive eczema.
authors.affiliation: Northwestern University, School of Medicine, Evanston, IL, USA.
authors.forename: S
authors.initials: S
authors.lastname: Ash
authors.forename: A J
authors.initials: AJ
authors.lastname: Scheman
mesh_terms: D000982:Antipruritics / Q000009:adverse effects*; D017449:Dermatitis, Allergic Contact / Q000209:etiology*; D003875:Drug Eruptions / Q000209:etiology*; D004485:Eczema / Q000139:chemically induced; D005029:Ethylenediamines / Q000009:adverse effects; D005260:Female; D006801:Humans; D006919:Hydroxyzine / Q000009:adverse effects*; D008875:Middle Aged; D010328:Patch Tests
chemical_list: D000982:Antipruritics; D005029:Ethylenediamines; D006919:Hydroxyzine; C031234:ethylenediamine