Hair Root Dermoscopy from Shed Hair: A Simple Diagnostic Tool in Telogen Effluvium

Sir,

Dermoscopy is commonly done to examine scalp and hair in patients with diffuse hair loss. Structures which may be visualized by trichoscopy include hair shafts of different types: vellus, terminal, micro-exclamation mark type, monilethrix, Netherton type, and pili annulati hairs. It is usually done on the scalp. Trichoscopy findings of telogen effluvium (TE) are not diagnostic and include short upright regrowing hairs and perifollicular hyperpigmentation. However, it helps to rule out the close differentials like diffuse alopecia areata (AA) and androgenic alopecia. We describe a case of TE where dermoscopy of the shed hair helped to make diagnosis.

A 20-year-old female presented with complaints of excessive shedding of hair of 10 days duration. The hair loss started 2 months after the episode of COVID infection. The midline parting was normal and the hair pull test was positive from all areas of the scalp. The patient had brought a bunch of shed hair in one day [Figure 1]. Trichoscopy of the scalp examined by handheld noncontact polarized dermoscope (DermLite, DL4) showed short upright regrowing hairs. Dermoscopic examination of the shed hair was performed, which revealed predominance of hair with depigmented club-shaped hair bulb suggestive of telogen hair [Figure 2]. Microscopy of the shed hair confirmed the findings on dermoscopy [Figure 3]. Based on these findings, a diagnosis of post-COVID acute TE was made.

Figure 1.

Bunch of shed hair in one day of the patient

Figure 2.

Dermoscopy of shed hair showing numerous depigmented and rounded up hair bulb (yellow arrow) representing telogen hair (DermLite DL4, polarized, ×10)

Figure 3.

Hair microscopy of the shed hair showing a telogen hair follicle with a nonpigmented cornified, club-shaped bulb. There was no attached root sheath seen

TE is a hair cycle disorder with excessive shedding of telogen hairs starting few months after the triggering event. It is primarily a clinical diagnosis, rarely requiring scalp biopsy to rule out other causes of hair loss. Trichogram or hair pluck test is used to examine hair roots which reveals an increase of telogen hairs (>25%),[1] but this requires a benchtop microscope. Microscopy can also confirm whether the pulled or shed hair is anagen or telogen. Trichogram, however, is a painful, semi-invasive test making it difficult to be performed in every case, and facility of microscopy is often not available at every center. Furthermore, it is difficult to visualize decreased pigmentation of hair roots on microscopy. The histopathology of the acute forms of TE is nonspecific and resembles that of normal scalp.[2] Dermoscope is a handy tool with constantly expanding uses in dermatology. There is not much published data on dermoscopy of TE. Empty follicles and numerous short regrowing hairs of normal thickness are the most common findings on trichoscopy of TE.[3] The dermoscopic findings of hair in situ do not provide any clue regarding the cause of the same. This is a diagnosis of exclusion. Nevertheless, dermoscopy reveals any subtle changes of pigmentation of hair roots of shed or pulled hair. Zhang et al. in their study performed dermoscopy of shed hairs and pulled hairs in patients with AA and acute TE. They found dermoscopy to be a useful tool to examine hair root pigmentation of the shed hair and distinguish between Diffuse AA and other forms of AA and TE.[4] Therefore, we suggest that dermoscopy can be a useful noninvasive tool to examine hair roots of shed hair in case of diagnostic dilemma.

Conflicts of interest

There are no conflicts of interest.

Funding Statement

Nil.