The baboon syndrome or intertriginous drug eruption: a report of eleven cases and a second look at its pathomechanism.

Although drug eruptions can mimic a variety of idiopathic skin diseases, this has not been mentioned in the differential diagnosis of intertrigo. We draw attention to an unusual presentation of a drug eruption with a characteristic distribution pattern that is confined to the intertriginous areas. This condition has been given one of the most memorable names in dermatology, the baboon syndrome. Originally, the baboon syndrome was described as a special form of systemic contact-type dermatitis (SCTD) that occurs after ingestion or systemic absorption of a contact allergen in individuals previously sensitized by topical exposure to the same allergen in the same areas. We present eleven cases of intertriginous eruptions that resulted from adverse drug reactions. A flare-up of a previous contact with the same allergen (i.e., drug) on the same areas is not a reasonable explanation for the unusual localization of the eruption in our and others' cases. We believe that we are dealing with a type of recall phenomenon and that the characteristic localization and appearance of the eruption is determined by an earlier, unrelated dermatitis that had occurred in precisely the same areas. Adverse drug reactions should always be considered in the differential diagnosis of intertrigo, especially in atypical and therapy-resistant cases.