Hair Casts

Hair Casts (syn: peripilar keratin casts)

Hair Casts present as non-adherent white or yellowish cylindrical collarettes with a length of 1-6 mm that encircle a hair-shaft and can freely slide along its length.

They present in small or large numbers at any scalp location.

Cross sectional microscopical examination reveals a central region of root-sheath cells surrounded by keratinised cells.

Hair casts may or may also not be associated with Pityriasis conditions (Pityriasis is a genus of non-pathogenic yeast-like fungi which produce fine spores but no mycelium). Pityriasis proliferates in ‘Dandruff ‘ and ‘Seborrhoeic Dermatitis’ and ‘Pityriasis Amiantacea’ and ‘Psoriasis of the scalp’.

Young females are at greatest risk of demonstrating hair casts.

Static hair casts may be confused with:

• White Piedra (a stone) – due to trichosporum cutaneum ( syn trichosporum beigelii ) – a yeast-like fungus which surrounds the hair-shaft and may eventually invade the cortex causing severance (trichorrhexis nodosa).

• Trichorrhexis Nodosa

• Pediculus Capitis

• Seborrheic Dermatitis

• Trichomycosis Nodosa.

Macroscopical or microscopical examination together with the will differentiate hair casts from the other possibilities.

Treatment: Soak the hair casts in acetic acid and comb them off the shaft at the distal end.

A Case Example

A Caucasoid female (23 years) presented with numerous hair-shafts bearing white accretions resembling the ova of pediculosis capitis. Pruritis was absent. Visual examination failed to locate parasites.

Diagnosis: confirmed through physical examination which revealed that the white collarettes could slide along the hair-shafts.



© 2001- B Stevens FTTS Contact the author