Tubular hair casts in trichoscopy of hair and scalp disorders

Introduction: Hair casts have been reported in a variety of hair and scalp disorders. Trichoscopy allows a quick and noninvasive method for the evaluation of hair and scalp disorders in high magnification. However, the study of hair casts seen in trichoscopy is lacking. Objective: The main objective is to study the occurrence and patterns of tubular hair cast (THC) in different hair and scalp disorders. Patients and Methods: The patients with hair and scalp disorders presenting at the dermatology department of our hospital were evaluated using trichoscopy. Cases of primary parakeratotic disorders and behavioral disorders were excluded. After a detailed history and evaluation of the hair and scalp, histopathology, light microscopic examination, potassium hydroxide examination, and fungal culture were done when necessary. Results: THC was seen in total 21 cases of seven different hair and scalp disorders. Of these, the majority of cases were of discoid lupus erythematosus (DLE) (5/21) and maximum frequency of THCs within a disorder was seen in cases of pemphigus foliaceus (PF) (50%). Proximal casts occurred in 90.47% of cases. Single cast involving two shafts was seen in a case of PF, and two casts within a single shaft were seen in two cases of DLE and one case of alopecia areata. Conclusions: THCs in trichoscopy can be seen in various hair and scalp disorders and their study may help during the diagnosis of those disorders when combined with other trichoscopic features.