A Clinical, Dermoscopic, and Histopathological Study of Follicular Psoriasis

Abstract

Introduction: Follicular psoriasis is one of the underdiagnosed clinical types of psoriasis. Literature is grossly limited to anecdotal case reports and series. Clinical and investigational aspects are not studied in depth.

Materials and methods: A study was conducted to determine the frequency of follicular psoriasis, which includes cases with an exclusive or substantial number of follicular lesions. We analyzed the clinical, dermoscopic, and histopathological features of follicular psoriasis in a descriptive study.

Results: A total of 117 patients with psoriasis were screened. An exclusive or substantial number of follicular lesions were found in 22 patients. Four patients had exclusively follicular lesions and others were psoriasis vulgaris with follicular psoriasis. Dermoscopy revealed perifollicular scaling and white homogeneous area with normal terminal hair in all cases. Vascular features were visible in 14 cases and all had dotted vessels, with four having additional globules. Twenty patients revealed one or more features suggestive of follicular psoriasis on histopathology.

Conclusion: Follicular lesions can appear exclusively or can coexist with plaque type of lesions in psoriasis. They may indicate early psoriasis lesions. Dermoscopy is a useful and rapid tool to confirm the diagnosis of follicular psoriasis. Histopathology, though confirmatory, demands an astute interpretational skill. Diagnosis of follicular psoriasis can have therapeutic implications.

Keywords: Dermoscopy; follicular psoriasis; histopathology.

Figure 1

(a) Grouped and discrete papules of follicular psoriasis. (b) Follicular papules with the confluence of follicular psoriasis to form plaques. (c) Follicular psoriasis involving the neck with flexural psoriasis of postauricular area. (d) Close-up view of follicular psoriasis. (e) Close-up view of follicular psoriasis

Figure 2

(a) Follicular scaly papules with the pink–white homogeneous perifollicular area. (b) Follicular scaly papules with the white–brown perifollicular area. (c) Perifollicular white scales with dotted vessels. (d) Perifollicular homogeneous white area with dotted vessels and dermoscopic Auspitz sign

Figure 3

(a) Follicular plugging, ostial parakeratosis with Munro's micro abscess with the normal interfollicular area (H and E, ×4). (b) Dilated follicle with hypogranulosis and elongated rete ridges involving the follicular and interfollicular epidermis (H and E, ×10). (c) Follicular plugging, hypogranulosis, elongated rete ridges, and perifollicular infiltrate (H and E, ×10). (d) Perifollicular lymphohistiocytic infiltrate (H and E, ×20)

Figure 4

High-resolution video dermoscopy image of follicular psoriasis showing vascular features