CONSIDERING both the increasing incidence and the increasing clinical awareness of pediculosis capitis, it is surprising that since 1961, when Rollins1 reported three cases of hair casts (peripilar keratin casts), or pseudonits, there have been, to my knowledge, no additional reports of this entity mentioned in the North American literature. Hair casts, or pseudonits, are 2-to 7-mm long, discrete, firm, shiny, white, freely movable tubular accretions that encircle the hair shafts of the scalp. Hair casts may be due to the persistence of the inner root sheath of the hair, which normally crumbles or is digested at the sebaceous gland opening (Fig 1 and 2).
The misdiagnosis of hair casts as pediculosis capitis or nits may have severe psychological or physiological consequences for the patients and their families.
Report of a Case
A 7-year-old girl was seen in consultation following a five-year history of having nits repeatedly diagnosed by
Kohn SR. Hair Casts or Pseudonits. JAMA. 1977;238(19):2058–2059. doi:10.1001/jama.1977.03280200070028
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