What type of rash is characterized by small white spots in the hair shaft?

The type of rash characterized by small white spots in the hair shaft is indeed related to pediculosis capitis, commonly known as head lice infestation. These small white spots represent the nits or eggs laid by lice, which are attached to the hair shafts near the scalp. Nits are often mistaken for dandruff, but they are firmly adhered to the hair and don’t easily come off with brushing. The presence of nits is one of the key indicators for diagnosing a lice infestation, along with symptoms such as itching and irritation caused by the lice.

In contrast, conditions such as nummular eczema, contact dermatitis, and psoriasis present differently. Nummular eczema appears as round, coin-shaped areas of inflammation on the skin, while contact dermatitis results from exposure to an irritant or allergen and involves more generalized skin reactions. Psoriasis is characterized by red, scaly plaques and does not involve hair shafts in the same way pediculosis capitis does. Understanding these distinctions is essential for accurately identifying and managing various dermatological conditions.