Fixed drug eruption due to loratadine.

We present the clinical case of a 8-years-old boy suffering a fixed drug reaction attributed to the oral intake of loratadine. He is an atopic child with perennial rhinitis and asthma and marked hypersensitivity to the house-dust mite Dermatophagoides pteronyssinus who is receiving inhaled corticosteroids and b2-agonists ad libitum plus specific immunotherapy with the mite. When the boy received loratadine to alleviate his nasal symptoms he suffered a well-defined erythematous and oedematous plaque in his right elbow that disappeared without treatment in one week. Several methods such as the patch-tests, the UBCT or ultra-brief-challenge test (our version of the peroral provocation one) and the skin biopsy were applied. The UBCT and the skin histopathology were the most important techniques to assure the suspected diagnosis. Other antihistamines such as ebastine and cetirizine as well as some excipients used as controls were all negative. Conventional prick or intradermal skin tests with the drug were not performed because we considered that they were useless in this case.