Flu-Like Syndrome, Bronchoconstriction and Fever Caused by 5-Methoxypsoralen: The First Case Report and Literature Review

Photochemotherapy with psoralens and UVA (PUVA) is a very effective therapeutic option based on the interaction of a photoactive drug and light usually employed for the treatment of psoriasis and of other skin disorders, such as atopic dermatitis, vitiligo, and cutaneous lymphoma. The psoralens most widely used for oral PUVA are 8-methoxypsoralen (8-MOP) and 5-methoxypsoralen (5-MOP), tricyclic furocoumarins naturally present in a large number of plants. The chemical formula and the molecular composition of 5-MOP and 8-MOP present only slight differences, however these are sufficient to make them two different chemical compounds capable of different reactions and interactions. PUVA is generally well tolerated, but adverse events may occur. Besides the photosensitizing effect, which represents the therapeutic basis of PUVA, the commonest side effects complained of by the patients after oral intake of psoralens are nausea, vomiting, anorexia (mainly for 8-MOP), insomnia, anxiety, headache. Although very rarely or exceptionally, a series of potentially serious side effects has also been referred: while anaphylaxis has been reported due to both oral 5-MOP and 8-MOP, exanthematous drug reaction, urticaria, bronchoconstriction, asthma exacerbation, drug fever and flu-like symptoms such as headache, fatigue, muscle aches have been published related to 8-MOP intake only. To our knowledge, in fact, none of the above mentionated symptoms have been associated to oral 5-MOP in literature.Our report describes a case of fever, bronchoconstriction and flu-like syndrome in a patient during PUVA therapy with oral 5-methoxypsoralen