Flu-like syndrome, bronchoconstriction and fever caused by 5-methoxypsoralen: the first case report and literature review.

Case Report A 53-year-old male anaesthetist with a widespread, histologically proven psoriasis vulgaris was treated with oral photochemotherapy (PUVA) after failure of multiple intensive topical treatments and poor response to UVA-UVB phototherapy. PUVA was begun according to our standard protocol: 2 h after oral administration of 5-MOP 100 mg (Geralen , 1.2 mg/kg body weight), the patient was irradiated with an initial UVA dose of 0.5 J/cm 2 . Then, UVA doses were gradually increased (mean of 0.5 J/cm 2 at each session) up to a maximal dosage of 7.5 J/cm 2 UVA 3 times a week, with a nearly complete resolution of the skin disease in about 2 months. The patient did not experience any side effects for the first 24 treatments, while he complained of high fever (39 ° C), bronchoconstriction (dyspnoea, thachypnoea and dry cough), malaise, headache and asthenia (flu-like symptoms), progressively increasing in severity, after the 25th, 26th and 27th treatments. These symptoms were reported to arise about 10 h after PUVA therapy and to abate spontaneously the day following the therapy. The patient was otherwise healthy and reported that he had felt well before each of the last 3 PUVA treatments. When PUVA was discontinued, no signs or symptoms appeared again. Three years before, the patient had undergone an annual course of UVA-UVB phototherapy without any kind of adverse reactions. There was no history of concomitant drug consumption, inflammatory diseases or infections. Blood analysis did not reveal any laboratory abnormalities neither before PUVA treatment nor after the drug reaction. Two months later, in order to evaluate if 5-MOP was the cause of the febrile-bronchoconstrictive-flu-like reactions, an oral provocation test was performed with the therapeutic dosage (100 mg) of 5-MOP without further UVA irradiation. Ten hours later, the patient complained of high fever (39 ° C), bronchoconstriction and flu-like symptoms like those he had experienced 2 months earlier. A phototest with UVA and UVB alone gave no adverse event. The recurrence of the same type and severity of clinical reactions after 5-MOP intake, as well as the absence of any signs and symptoms after the phototest, strongly suggested that only 5-MOP could be considered the cause of the side effects. The patient refused to undergo any further provocation test with ‘placebo tablets’ (containing all constituents of the Geralen capsule except 5-MOP) to verify a possible causal role of the excipients contained