Fixed drug eruption: primary site involvement on maximal points of Head's zones.

The principles behind the primary localization of lesions in fixed drug eruption are still unknown. Studies investigating the predilection areas indicated drug-related, trauma-related or inflammation-related specific site involvement in fixed drug eruption. This study presents new findings of primary site involvement on the maximal points of Head's zones. In the 3 cases reported here, fixed drug eruption lesions were located at specific sites; the so-called maximal points of Head's zones, which are known to be the most active dermatomal areas of an underlying visceral pathology. An underlying internal disturbance was found in all 3 patients, corresponding to the organ-related maximal point of Head's zones in each case. In conclusion, the primary location of the fixed drug eruption lesions on the maximal points of the Head's zones according to the well-known neurophysiological map is an important observation in studying the predilection areas.