Trichorrhexis invaginata
Pronunciation: trik-oh-REK-sis in-VAJ-ih-NAH-tah
A pathognomonic hair-shaft abnormality seen in Netherton syndrome, in which the distal hair segment invaginates into its own proximal portion, creating a 'bamboo hair' appearance.
Full Definition
Trichorrhexis invaginata is a structural hair-shaft defect in which the keratinised distal portion of the hair invaginates into the softened proximal segment, forming a ball-and-socket or 'bamboo node' deformity visible on light microscopy. It is the hallmark trichoscopic finding of Netherton syndrome and results from defective cornification due to serine protease dysregulation. Editors should note the correct spelling ('invaginata,' not 'invaginata') and that it is typically presented in italics when used as a full diagnostic term in Latin, but rendered in roman text in standard English clinical prose.
Usage
Usage note: Do not italicise in standard English clinical prose. Distinguish clearly from trichorrhexis nodosa (a different hair-shaft fragility disorder) in any document referencing hair abnormalities.
In Context
- "Light microscopy of the scalp hair confirmed trichorrhexis invaginata, supporting the clinical diagnosis of Netherton syndrome." — Dermatopathology report
- "The section on hair-shaft disorders should distinguish trichorrhexis invaginata from trichorrhexis nodosa, as the two are frequently confused." — Textbook editorial note