Hair casts: classification, staining characteristics, and differential diagnosis

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.

Traction alopecia: the root of the problem

Traction alopecia (TA) affects one-third of women of African descent who wear various forms of traumatic hairstyling for a prolonged period of time. The risk of TA is increased by the extent of pulling and duration of traction, as well as the use of chemical relaxation. The frequent use of tight buns or ponytails, the attachment of weaves or hair extensions, and tight braids (such as cornrows and dreadlocks) are believed to be the highest risk hairstyles. TA can also occur in the setting of religious and occupational traumatic hairstyling. In its later stages, the disease may progress into an irreversible scarring alopecia if traumatic hairstyling continues without appropriate intervention. The most common clinical presentation includes marginal alopecia and non-marginal patchy alopecia. A clue to the clinical diagnosis is the preservation of the fringe sign as opposed to its loss in frontal fibrosing alopecia (FFA). Dermoscopy can be helpful in the diagnosis and can detect the ongoing traction by the presence of hair casts. Histopathology can distinguish TA from alopecia areata, FFA, and patchy central centrifugal cicatricial alopecia. Currently, there is no cure. Therefore, it is imperative that clinicians educate high-risk populations about TA and those practices that may convey the risk of hair loss.

Adult Onset Hair Casts: Nits Which Do Not Itch!

Hair casts (HCs) are thin, elongated, firm, whitish cylindrical concretions which ensheath the hair shaft and can be easily dislodge. They are of two different types: peripilar and parakeratotic keratin cast. Due to its clinical resemblance to pediculosis capitis, the entity is also known as pseudonits. Al though not unusual, false diagnoses are common, and thus, it is very important to correctly differentiate it from other similar conditions. We report here a case of HC involving scalp as well as body hair in association with androgenetic alopecia in a 22-year-old male patient. The patient's sister was also affected with pseudonits.

Evaluation of clinical signs and early and late trichoscopy findings in traction alopecia patients with Fitzpatrick skin type II and III: a single-center, clinical study

BACKGROUND

Traction alopecia refers to (often permanent) hair loss caused by prolonged physical damage. No study has yet described the unique trichoscopic findings of the condition. We describe the trichoscopic findings of traction alopecia and its relationships with the duration of traction.

METHODS

We studied 25 patients who were clinically diagnosed with traction alopecia. The patients were divided into two groups in terms of traction duration. Trichoscopy was performed at a minimum of two scalp locations in each patient.

RESULTS

Reduction in hair density, hair diameter diversity, empty follicles, and vellus hairs were observed in all patients. In addition, the following were observed: loss of follicular openings in 19 (76%) patients, yellow dots and broken hairs in 17 (68%), black dots in 12 (48%), hair casts in 7 (28%), circular hairs in 5 (20%), and arborizing red lines in 3 (12%). The trichoscopic findings varied with the duration of traction.

CONCLUSIONS

Traction alopecia is a chronic condition that is difficult to treat. Trichoscopy can be used for diagnosis. Our study is the first to identify the early and late trichoscopic features of traction alopecia. The limitation of the study is the lack of histologic diagnosis.

Generalized hair casts due to traction

Peripilar keratin casts, also called pseudonits or hair casts, are thin, elongated, greyish-white, cylindrical, sleeve-like structures that encircle the hair shaft and can easily be slid along the hair. They may be clinically misdiagnosed as nits. In addition to physical removal, keratolytic lotions or shampoos are helpful. We report an 11-year-old girl with pseudonits. Although it is not a rare condition, underdiagnosis is common.

Is propionibacterium acnes associated with hair casts and alopecia?

We report a series of four patients who presented with complaints of diffuse non-scarring alopecia. They had similar clinical features of alopecia, hyperseborrhea, and distinct keratinaceous hair casts that encircled the hair shafts. Propionibacterium acnes was isolated from two of the patients' scalp, and Gram-positive, Giemsa-positive bacteria were seen in the hair follicles in the scalp biopsy of one of the patients. The patients' symptoms did not respond to standard treatment for seborrheic dermatitis, but responded to a course of systemic antibiotics targeting P. acnes. We propose a role for P. acnes colonization of the terminal hair follicles in the pathogenesis of hair casts, and possibly diffuse non-scarring alopecia. Possible mechanisms of pathogenesis are discussed with a literature review.

Female adolescent hair disorders

Hair abnormalities can have tremendous psychosocial impacts on adolescents and young adults, and may cause a great amount of anxiety regarding physical appearance, associated illnesses, and potential clinical course. The pathophysiology of such disorders may vary,with potential congenital, infectious, autoimmune, nutritional, or environmental causes. Hair abnormalities may present as changes in hair appearance or quality, becoming weathered or fractured.An abnormal increase in hair is present in hypertrichosis and hirsutism, whereas a thinning or shedding of hair is evident in patients with telogen effluviumand alopecia areata. Diagnosis is focused on a detailed clinical history and physical exam, in addition to laboratory testing, a variety of clinical diagnostic tests, and scalp biopsy, which may be necessary to confirm some diagnoses. Many hair disorders have no cure, but clinicians can have a positive impact on their patients by identifying the abnormality and educating the patient regarding disease course. However, some conditions such as infectious hair disorders or scarring alopecia should be identified promptly to initiate treatment and ensure clinical improvement or optimal outcome.

Hair casts due to a deodorant spray

A 7-year-old girl presented with itching and greyish-white sleeve-like structures in her hair. After ruling out other possible causes for the symptoms, such as nits and dandruff, it was determined that the patient was affected by hair casts. These are small cylindrical structures resembling louse eggs that encircle individual scalp hairs and are easily movable along the hair shafts. It was concluded that she had induced the condition through misuse of a deodorant body spray. Scanning electron microscopy combined with electron dispersive X-ray analysis (X-ray microanalysis) of the hair casts showed the chemical nature of the structures. Some elements present in the composition of the ingredients of the deodorant spray, such as aluminium, chlorine, silicon, magnesium and carbon, were also present in this uncommon type of hair casts.

Epidemiological and aetiological studies on hair casts

Hair casts (HC) appear to have become more common in young adults. An investigation on the incidence of HC was made in the Chengdu district of China. Of 3548 individuals surveyed, 30.24% suffered from HC. HC were restricted to females, among whom the incidence was 61.6%. HC is thus a very common finding. Long-term and frequent traction imposed on hair with excessive force appears to be the major cause of HC. This was confirmed from braiding studies which consisted of traction by tightly drawn braids on healthy subjects, together with histopathology of the underlying skin and statistical data on the frequency of HC.

Hair casts: a clinical and electron microscopic study

Hair casts were seen in 22 girls ranging in age from 4 to 13 years. They were localized to the frontal, vertex, and temporal areas. The number of affected hairs varied from one-tenth to one-third. Twenty of the 22 girls styled their hair in ponytails or pigtails. Compound root sheath casts were present in six of nine patients using 1% 4-dimethylaminocinamaldehyde stain. A mass of large polymorphous scales and solitary or clumped spores was seen on the surface of hair casts using scanning and transmission electron microscopy. Energy-dispersive x-ray microanalysis showed that elements of silicon, aluminum, and molybdenum were uniquely present in hair casts. We assume that tightly drawn braids, by causing local circulatory disturbances and inflammation of the scalp, may be one etiologic factor in the disorder.

Structural abnormalities of the hair shaft

Abnormalities of the hair shaft are varied and often confusing. They do require accurate recognition, which can be helpful in the diagnosis and management of a hair disorder, or in the detection of underlying disease. A reliable evaluation of hair shaft abnormality is dependent on familiarity with the vast structural variations in normal hair, the hair growth cycle, and the changes produced by weathering. These structural abnormalities can be congenital or acquired, and some are associated with hair fragility. The classification used here has the advantage of simplicity and is keyed to easy recognition of the abnormalities under the light microscope. The four major types of abnormality are fractures, irregularities, twisting, and extraneous matter affecting the hair shaft. The diagnostic features of the different hair shaft abnormalities are outlined.