Sir.We report here a case of a patient with chronic psoriatic arthritis affecting multiple joints, in whom an unusual cutaneous reaction with hyperpigmentation of the face developed following treatment with adalimumab.
CASE REPORTA 52-year-old man with a 17-year history of chronic psoriatic arthritis affecting multiple joints developed an unusual cutaneous reaction with hyperpigmentation of the face following treatment with adalimumab.Before treatment he had had only mild psoriasis of the skin., limited to a single lesion located behind one ear. For several years he had been treated with methotrexate (MTX) 12-15 mg weekly (cumulative dose approximately 12.000 mg) and ibuprofen 400 mg daily, but his arthritis deteriorated, resulting in a need for an alternative treatment. He did not have any other diseases and did not smoke tobacco. He had an average daily alcohol consumption of 8 units (1 U equals 33 cl of standard beer or 12 cl of non-fortified wine).At the beginning of April 2008 he commenced adalimumab 40 mg subcutaneously, every second week, concomitant with his stable dosage of MTX and ibuprofen. Following 2 weeks of adalimumab treatment there was no further need for analgesics, and ibuprofen was henceforward only taken when necessary, approximately twice monthly.In May 2008, 4-5 weeks after initiating adalimumab treatment, the patient was exposed to a considerable amount of sun during sun-bathing. He developed a reddish colour followed by a darker hyperpigmentation of the face, remarkably with a periorbital zone of apparently normal skin, even though he did not wear sunglasses (Fig. I ). His arms and legs were also heavily exposed to sunlight (not sunburned), but only the face was affected by hyperpigmentation. The patient experienced no other symptoms.The results of the following tests were either negative or within normal limits: haemoglobin, white blood cell count, se-creatinine, se-iron. alanine aminotransferase. lactate dehydrogenase. alkaline phosphatase, gamma-glutamyltransferase, platelets. C-reactive protein level, antinuclear antibodies, DNA-anti bod i es and urine porphyrins. Se-aspartate aminotransferase (ASAT) was increased to 74U/l(range 15-45 U/l). but later normalized without effect on the hypeipigmentation. Hislopathological examination of a 2 mm punch biopsy from the right chin revealed enlarged epidemial keratinocytes and hyperkeratosis as a result of earlier hydropic basal cell degeneration. Superficially in dermis there were many melanophages and a modest, mainly perivascular, lymphocytic infiltrate, consistent with post-inflammatory hyperpigmentation. The hyperpigmentaFig.