Trichoscopic Signs of Netherton Syndrome: A Comprehensive Case-Based Insight

Netherton syndrome (NS) is a rare autosomal recessive genodermatosis characterized by a triad of ichthyosis linearis circumflexa, atopic diathesis, and distinctive hair shaft anomalies. Its diagnosis is often delayed, particularly in early infancy, due to incomplete or nonspecific clinical presentations. Among the cutaneous manifestations, hair shaft anomalies tend to present early and provide highly specific diagnostic clues. We report the case of a six-month-old girl presenting with persistent pruritic and scaly dermatitis, associated with short, dull scalp hair and sparse eyebrows. Trichoscopic examination revealed a rich combination of hair shaft anomalies, including trichorrhexis invaginata (bamboo hairs), matchstick hairs, golf tee hairs, pili torti, and trichorrhexis nodosa. These findings, although underdocumented in the literature, are highly specific and collectively supported the diagnosis of NS in the absence of ichthyosis linearis circumflexa or initial genetic confirmation. This case highlights the essential role of trichoscopy as a rapid, non-invasive diagnostic tool in infants with unexplained xerosis, flexural dermatitis or erythroderma. Early recognition of NS through its trichoscopic features can guide appropriate management and timely referral for genetic counseling, even in the absence of full phenotypic expression.