Dermoscopy of Nits and Pseudonits
After a recent outbreak of head lice at school, two 15-year-old girls presented with itching of the scalp. Dermoscopy of the hair of one girl revealed one vital nit and one empty nit shell attached to the hair shaft, confirming the diagnosis of pediculosis capitis (head-lice infestation). The vital nit, filled with an embryo, was a brown, ovoid structure with a convex end (Panel A, red line), whereas the empty, hatched nit was translucent with a planar end (Panel A, blue line). In contrast, dermoscopy of her classmate's hair showed white, bizarrely shaped, amorphous structures that were consistent with pseudonits, which are peripilar keratin casts, or hair casts (Panel B). Hair casts, due to dandruff, can be easily confused with head lice. Dermoscopy allows the immediate and reliable diagnosis of head-louse eggs and their differentiation from pseudonits. Moreover, dermoscopy aids in the distinction between the vital nits of an active infestation and hatched, empty eggs, allowing for the monitoring of treatment success or failure.
Dermoscopy is very helpful especially in pigmented lesions of skin.must be done with skin specialist.used to differentiate between benign and malignant lesions of skin.
