Parakeratotic comedones of the scalp, or hair casts, have been described recently by Kligman2 and Brunner and Facq.1 These keratin cylinders around the hair shaft usually occur in young girls. Clinically, they are yellowish-white, firm cylinders, usually 3 to 7 mm. in length. Owing to their lack of attachment, they move freely up and down the hair shaft. Their fluorescence under the Wood's light is of a bluish-yellow hue.
Although dermatologists have long been aware that prolonged traction on the scalp hair may produce baldness, this fact failed to attract the attention of the lay public until lately. Twenty-four cases of traction alopecia were reported by Slepyan3 in 1958. This syndrome, caused by traction on the hair, usually traction from "pony tails," consists of erythema and follicular pustules and alopecia. Although these entities have been described separately, we have failed to notice any report in the literature
ROLLINS TG. Traction Folliculitis with Hair Casts and Alopecia. Am J Dis Child. 1961;101(5):639-640. doi:10.1001/archpedi.1961.04020060097013