Involvement tends to follow dermatomes of the fifth cranial nerve.
Clinical features:
(1) hemifacial atrophy with facial asymmetry, rarely bilateral
(2) changes in the brain on the same side as the facial atrophy, especially in the white matter
(3) enophthalmy (deviation of mouth and nose towards the affected side)
(4) dental abnormalities (delayed eruption, root atrophy, crossbite, mandibular hypoplasia, loss of maxillary bone)
(5) tongue hemiatropahy
(6) skin changes in affected areas: atrophy, skin pigmentation, linear morphea (sclerotic plaque), coup de saber at point of transition
(7) numbness with weakness in the affected area
(8) variable difficulties with speech and mastication
(9) variable atrophy of fat, muscle and bone on the affected side
(10) variable eye involvement (corneal atrophy, phthisis of the globe, blindness)
(11) rarely may affect other parts of the body (unilateral or bilateral)
Classification of Guerrerosantos et al:
(1) Type 1: weakness and slight depression of facial structures
(2) Type 2: greater weakness without loss of bone or cartilage
(3) Type 3: loss of bone and cartilage with facial deformity
(4) Type 4: very severe atrophy with advanced loss of bone and cartilage
