We report the case of a a 60 year-old worker in the pharmaceutical industry who suffered from recurring
contact dermatitis. Initially the
contact dermatitis was limited to the hands; later on it became generalized. The patient had been working on a
drug filling line in a pharmaceutical plant for more than 20 years. Eight years after starting this job he had developed allergic hand
dermatitis to
2,6-diaminopyridine (patch test positive); this healed upon cessation of exposure. Ten years later he again developed hand
dermatitis which progressed to generalized
dermatitis and
conjunctivitis. Under systemic and local
therapy with
corticosteroids and cessation of work, it healed nearly completely. Four months after returning to work, the patient experienced a first episode of severe
asthma and generalized
dermatitis with
conjunctivitis following exposure to
hydroxychloroquine the day before. The
asthma and
dermatitis improved after systemic
corticosteroid therapy and stopping work. His condition continued to fluctuate, when though the patient was transferred at work and now wore rubber gloves. Eight months later he again developed a generalized
dermatitis. Patch testing revealed delayed-type sensitizations to
hydroxychloroquine (tested in concentrations of 0. 1%, 0.5%, 1% and 2%). Equivalent tests in five healthy volunteers were negative. The patch test reactions were pustular, while a biopsy was interpreted as a multiform
contact dermatitis reaction. Bronchial exposure with
hydroxychloroquine dust produced a delayed bronchial obstruction over the next 20 hours, which progressed to
fever and generalized
erythema (hematogenous
contact dermatitis). After removing exposure to
2,6-diaminopyridine and
hydroxychloroquine, the patient went on to develop a
contact dermatitis to
latex (patch test positive). However, skin prick tests with
latex and patch tests with rubber additiva were negative.
Hydroxychloroquine is well known to cause
drug reactions. To our knowledge,
contact dermatitis to this substance has not yet been reported. It is noteworthy that the patch test reactions were pustular and of multiform morphology and that bronchial exposure to the
allergen resulted in
asthma and a generalized
drug reaction. Pathogenetically the asthmatic reaction seems to be on a delayed-type mechanism as is also seen with
ampicillin,
cobalt and
nickel induced
asthma.