hypotrichosis

Hypotrichosis is a group of conditions characterized by reduced hair density and abnormal hair growth. It can affect scalp hair and other body hair, such as eyebrows and eyelashes. The onset is usually congenital or early in life, and the severity ranges from minor to extensive sparseness. The term covers isolated (non-syndromic) hypotrichosis and syndromic forms in which sparse hair occurs with other physical abnormalities or retinal disease.

Non-syndromic forms include hypotrichosis simplex, in which hair is sparse without other major anomalies. Syndromic forms include hypotrichosis with juvenile macular dystrophy (HJMD), caused by mutations in CDH3 and inherited in an autosomal recessive manner, featuring sparse hair with progressive macular dystrophy; and atrichia with papular lesions (APL), caused by mutations in the HR gene and usually presenting with early hair loss followed by papules on the skin as hair follicles arrest.

Genetics: Many genes are implicated in hair follicle development and cycling; inheritance patterns include autosomal dominant and autosomal recessive depending on the form.

Diagnosis: Based on clinical evaluation, family history, and confirmation by genetic testing. In rare cases, hair shaft or skin biopsy analyses may be used.

Management: There is no cure to restore normal hair growth; management is supportive and cosmetic, including wig or prosthesis, and treatment of associated retinal or skin problems in syndromic forms.

Prognosis: Variable. Non-syndromic hypotrichosis generally has a stable course; syndromic forms may involve progressive ocular or other organ involvement and require multidisciplinary care.