Itchy black hair bristles on back.

INTRODUCTION

A 27-year-old male presented with gradually erupting itchy black hair bristles on inter-scapular region for the past 6 months. His past medical or family history was unremarkable. Hairs could be plucked easily by his friend without any discomfort to him. Examination revealed multiple follicular blackish hair bristles, the size of pinheads (0.5-1 mm) on inter-scapular region [Figure 1]. Few large size bristles were plucked for trichogram [Figures 2 and 3]. However, patient denied skin biopsy.

Figure 1

Multiple follicular black hair bristles over inter-scapular region

Figure 2

A trichogram showing numerous vellus hairs embedded in a hyperkeratinoussheath with typical paint brush appearance (trichogram, ×40)

Figure 3

(a) Hair roots showing typical telogen hairs with keratinous sheath (trichogram, ×40). (b) High power view of hair tips showing paint brush appearance (trichogram, ×100)

WHAT IS YOUR DIAGNOSIS?

Answer

Trichostasis spinulosa (TS).

DISCUSSION

TS is a common but an often unrecognized disorder of the pilosebaceous unit. It results from follicular hyperkeratosis of a dilated vellus hair follicle leading to retention of successive telogen hairs. Number of retained hairs may range from 5 to 60. Both sexes are affected similarly.[12]

The etiology of TS has aroused much speculation, including the role of congenital dysplasia of the hair follicles and external factors like dust, oils, ultraviolet light, heat, and irritants but exact etiology remains unknown.[12] Recently, micro-organisms, in particular, Propionibacterium acne and Pityrosporum spp. are also claimed as one of the possible etiologic factors.[3] A case of TS attributed to application of clobetasole cream[4] and a case of terminal hair TS resulting from local application of minoxidil is reported.[5] Moreover a case of generalized TS in a chronic renal failure patient is also reported.[6]

The disorder was first recognized by the German dermatologist Felix Franke in 1901, who named it “Pinselhaar” (paintbrush hair).[2] In 1913, Noble first introduced the term “trichostasis spinulosa” when he reported six cases with spiky follicular papules due to vellus hair retention.[7]

Two variants of TS are believed to exist. The classical variant presents with a non-itchy, solitary lesion, especially on the nose, mimicking open comedone in the elderly. The other, pruritic variant manifests with multiple, itchy, follicular papules, mainly located on the trunk and arms in young adults. Inter-scapular region is affected commonly as in present case. Due to the location and lack of awareness about this variant, it is often mistaken for keratosis pilaris.[2]

Treatment of TS is often frustrating on to both patient and doctor, and disease often follows a chronic course. Emollients, hydroactive adhesive tapes, local keratolytics, local and oral retinoids, and several means of depilation are tried with variable success. But topical treatments do not offer permanent benefit.[12] Permanent removal of the abnormal follicles using hair removal lasers may result in a definite cure.[8]

In conclusion, try to focus attention to pruritic variant of TS affecting inter-scapular region in young adult that often remains unrecognized. Moreover, importance of plucking few hairs for trichogram is demonstrated. We suggest “Mount the hair” should become the dictum similar to old dictum in dermatology “scrape the scale.“