Tuft of hair at an unusual location.

Sir,

Localized hypertrichosis is defined as the presence of a tuft of terminal hair in a patchy distribution. The most common location is in the midline over the lumbosacral region suggesting an underlying developmental defect.[1] We recently encountered an interesting patient with localized hypertrichosis over an unusual location.

A 19-year-old male presented with a history of chest pain after sustaining a blunt injury. He denied a history of cough and breathlessness. Physical examination revealed normal vital parameters and no evidence of any bony injury of rib cage. Chest examination revealed presence of a localized, well-circumscribed patch of terminal hair over the left scapula [Figure 1]. The color of the hair was black corresponding to his scalp hair and the skin over the patch was normal without any hyperpigmentation. On further questioning, the parents acknowledged the presence of this patch since birth and never sought consultation for the same. He is the second child of a non-consanguineous marriage and had normal developmental milestones. Detailed clinical examination revealed no dermatologic, skeletal or systemic abnormalities in the patient and family members. Routine hematological and biochemical parameters were normal and skin biopsy revealed presence of increased number of hair follicles. He was diagnosed as a case of nevoid hypertrichosis and was advised hair reduction laser therapy.

Figure 1

Patch of hair over left scapula

Congenital localized hypertrichosis is seen in only few conditions such as Becker's nevus, congenital melanocytic nevi, nevoid hypertrichosis and sacral midline developmental defect.[2] The differential diagnosis is difficult at times with overlapping clinical features. Becker's nevus manifests usually during puberty and absence of underlying pigmentary nevoid changes exclude the diagnosis of melanocytic nevi.[3] The presence of hypertrichosis in midline suggests developmental malformations like spina bifida occulta and diastematomyelia. In these conditions other cutaneous manifestations are sacral dimple, lipoma and a port-wine stain.

Nevoid hypertrichosis is the presence of a solitary area of terminal hair growth present since birth. The lesions are usually single and rarely multiple. The histopathology shows the presence of increased number of hair follicles in the dermis with normal overlying epidermis. This is associated with various systemic abnormalities like retinal hyperpigmentation, skeletal anomalies and lipodystrophy.[4] The cutaneous lesions usually persist through life, though spontaneous resolution is described. Laser therapy using neodymium-doped yttrium aluminum garnet laser is commonly used for hair reduction. Antiandrogens like spironolactone are also used in the management of Becker's nevus for associated abnormalities like breast hypoplasia.[3]