An infant has generalised erythroderma with fine white scaling since birth, failure to thrive, and markedly elevated serum IgE. Hair examination under light microscopy shows nodes along the shaft where the hair telescopes into itself. The diagnostic finding is called:

• A Trichorrhexis nodosa
• B Trichorrhexis invaginata (bamboo hair) ✓
• C Pili torti
• D Monilethrix

Explanation

Netherton syndrome (SPINK5/LEKTI defect) presents as congenital ichthyosiform erythroderma, atopy with very high IgE, and trichorrhexis invaginata, where the distal hair shaft invaginates into the proximal shaft producing bamboo nodes. Pili torti shows flattened twisted shafts in Menkes disease, and monilethrix shows periodic beading, neither of which occurs in Netherton syndrome.

Reference: Rook's Textbook of Dermatology, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.