Hair Casts

Deposits from Creams Containing 20% (w/w) Urea and Suppression of Crystallization (Part 1): Rate of Crystallization from Cream Containing 20% (w/w) Urea and Evaluation of the Properties of the Deposit

“…This study (1) confirmed the slow rate of urea crystallization in an LEC formulation when compared with an NS formulation and urea aqueous solution under winter-like low humidity conditions (humidity: 40-50%; temperature: 20-25°C).…”

“…The softening effect on the stratum corneum generally increases with the urea content of the cream. 1,2) Urea is more readily transferred to the stratum corneum in the dissolved (amorphous) state 3) and exhibits higher clinical efficacy when compared to crystalline urea; consequently, preparations are formulated to suppress crystallization 4) and thus maintain easy absorption. 5) External preparations that crystallize post-application exhibit drastically decreased transfer of urea to the skin 6) and may feel taut or gritty, and irritate the skin.…”

Tubular hair casts in trichoscopy of hair and scalp disorders

“…After the first description of hair cast by Klingman in 1957,[1] few authors have described and classified the HCs based on their composition. [23] Brunner[10] described them as persistent hair root sheaths that had failed to disintegrate.…”

Hair casts or pseudonits

“…[78] This characteristic is of paramount importance in their diagnosis and helps in differentiating them from other scalp disorders, such as pediculosis capitis, piedra, trichomycosis, trichonodosis and trichorrhexis nodosa. [9–11] As is often the case, hair casts may initially be misdiagnosed as the nits of pediculosis capitis [Table 1].…”