Hypertrichosis

Hypertrichosis is a condition characterized by excessive hair growth on the body that cannot be explained by normal variation in age or sex. Hair may cover large areas of the body (generalized hypertrichosis) or occur in localized patches, and it may be present at birth (congenital) or develop after birth (acquired). It is distinct from hirsutism, which refers to androgen-driven excess hair growth in women in a pattern typically associated with masculinization.

Classification commonly divides hypertrichosis into congenital generalized hypertrichosis, congenital localized forms (such as hypertrichosis lanuginosa), and acquired hypertrichosis. Ambras syndrome is a historical term for a congenital generalized form described in a family. Acquired hypertrichosis may follow exposure to certain medications, systemic illnesses, malnutrition, or hormonal changes, and may be reversible or persistent.

Genetic factors are implicated in several congenital forms; inheritance patterns can be autosomal dominant, autosomal recessive, or sporadic, and specific gene mutations have been described in a few cases. Acquired forms are linked to drugs such as minoxidil, cyclosporine, diazoxide, and certain anticonvulsants, as well as chronic illness or malnutrition.

Diagnosis relies on clinical examination and history, with evaluation for endocrine causes if indicated (for example, androgen excess). Treatment is not curative for congenital hypertrichosis; management focuses on cosmetic hair reduction methods (depilation, waxing, electrolysis, laser therapy) and psychosocial support. If an acquired cause is identified, addressing the underlying factor is appropriate and may reduce hair growth.

Prognosis varies with the underlying cause; congenital forms generally persist, while acquired forms may improve after removal of the trigger.