Nummular headache with trophic changes inside the painful area.

Nummular headache (NH) is a primary disorder characterized by chronic pain that is exclusively felt in a small area of the head surface. We describe five patients with circumscribed head pain and sensory dysfunction consistent with NH, who in addition developed colocalized trophic changes. All of them had a round or oval patch of skin depression (1-2 cm in diameter) inside of the painful area (2-4.5 cm in diameter). Three of them also showed hair loss, reddish colour, and local increased temperature. Skin biopsies were performed in three patients, and were not specific for any particular dermatological disease. Local trophic changes may be a clinical feature of NH. Together with pain and sensory disturbances, they could represent a restricted form of complex regional pain syndrome. This should be taken as a possible evolution of the underlying morbid process of NH.