Asymmetrical growth of scalp hair in syringomyelia

Trophic alterations in the skin take place consequent to interruption of its motor, sensory, and autonomic innervation. The hair in denervated areas is often less abundant and grows more slowly. Syringomyelia is a common cause of cutaneous trophic alterations that are often unilateral. They occur predominantly in the upper extremities and seldom involve the skin over the face and scalp. A patient with syringomyelia exhibited a unilateral impairment of pain and temperature sensation in the entire right side of the scalp. A dissimilarity of hair length between the right and left side of the scalp was noticed, with a sharp demarcation along the midline. This peculiar trophic change has not been previously described in the medical literature.