Trichorrhexis nodosa (TN) is the most common hair shaft anomaly, caused by either physical or chemical trauma. It presents with minute grayish nodes along hair shaft and characteristic “thrust paint brushes” appearance on microscopy. It may be congenital or acquired.
TN, the most common hair shaft disorder, appears as minute grayish nodes along the hair shaft. These nodes represent loss of cuticle along with frayed cortical fibers. On light microscopy, these changes appear like two paint brushes thrust into one another.
TN may be congenital or acquired, localized or generalized. Congenital TN may be present at birth, appear within the first year of life, or present as a symptom of an underlying metabolic disorder like argininosuccinic aciduria, Menkes’ kinky hair syndrome, Netherton syndrome, and Laron syndrome at the age of 2 years or later. It affects beard, moustache, eyebrow, eyelashes, axillary and pubic hairs variably along with scalp hairs. Breakage of hair occurs both at proximal and distal shaft.
Acquired TN usually occurs due to physical or chemical trauma to hairs and affects mostly scalp hairs only, with distal shaft breakage.Trichoscopy is one of the recent advances in diagnostic dermatology. It allows examination of subtle clinical patterns of skin lesions and subsurface skin structures not normally visible to the unaided eye. Trichoscopy has been used for rapid diagnosis of some hair shaft disorders like monilethrix. In our case, use of trichoscopy provided rapid and reliable diagnosis of TN.