Indian Dermatology Online Journal

THROUGH THE DERMOSCOPE
Year
: 2019  |  Volume : 10  |  Issue : 5  |  Page : 613--614

Dermoscopy of keratosis pilaris


Sidharth Sonthalia1, Jushya Bhatia2, Mary Thomas3,  
1 SKINNOCENCE: The Skin Clinic, Gurugram, Haryana, India
2 Department of Dermatology, Venereology and Leprosy, Sri Aurobindo Medical College and Post-graduate Institute, Indore, Madhya Pradesh, India
3 Department of Dermatology, Poornima Hospital, HMT Layout, RT Nagar, Bengaluru, Karnataka, India

Correspondence Address:
Mary Thomas
18, Pearson Street, Guelph, Ontario
India




How to cite this article:
Sonthalia S, Bhatia J, Thomas M. Dermoscopy of keratosis pilaris.Indian Dermatol Online J 2019;10:613-614


How to cite this URL:
Sonthalia S, Bhatia J, Thomas M. Dermoscopy of keratosis pilaris. Indian Dermatol Online J [serial online] 2019 [cited 2020 Sep 26 ];10:613-614
Available from: http://www.idoj.in/text.asp?2019/10/5/613/255538


Full Text



A 21-year-old man with atopic diathesis presented with multiple pin-head-sized erythematous to light brown-colored, non-scaly, keratotic follicular papules, closely clustered over the anterior aspect of thighs [Figure 1] and outer arms for past 6–7 years, associated with occasional itching. His sibling had similar lesions. There was no evidence of facial/truncal acne, seborrheic dermatitis, or spiny papules over the knees or elbows. Palms, soles, nails, and mucosae were unremarkable. A differential diagnosis of keratosis pilaris (KP), follicular psoriasis, phrynoderma, and pityrosporum folliculitis was considered.{Figure 1}

Polarized dermoscopy from thigh lesions revealed a faint reddish-light brown background with scattered vascular ectasias, twisted hairs forming loops and irregular coils, and vellus hairs [Figure 2]a. Dermoscopy from the outer arm additionally revealed perifollicular papular erythema, hairs emerging in groups of 2–3, focal peripilar casts, and scattered pigmented globules [Figure 2]b. Basket weave and lamellated orthokeratosis, follicular infundibular dilatation and plugging with focal peri-infundibular parakeratosis, perifollicular lymphocytic infiltrate, and absence of yeast cells on histopathology [Figure 3] confirmed the clinicodermoscopic diagnosis of KP.{Figure 2}{Figure 3}

KP, characterized by clustered 1 mm-sized, folliculo-centric keratotic papules with surrounding erythema, typically involving the extensor aspect of forearms and thighs is a common autosomal dominant dermatosis.[1],[2] Common differentials include phrynoderma, follicular psoriasis, seborrheids, truncal acne, and folliculitis. Although skin biopsy is diagnostic, dermoscopy facilitates instant non-invasive diagnosis of this benign condition.

The exact pathogenesis of KP remains unclear. The likelihood of KP being a disorder of keratinization has been challenged by Thomas and Khopkar, based on their dermoscopic findings.[3] They have suggested the coiled hair shaft to be central to its histogenesis that ruptures the follicular epithelium leading to inflammation and abnormal follicular keratinization.

Dermoscopic features of KP include presence of vellus hairs that are frequently coiled, semi-circular or looped, peri-follicular erythema, and peri-pilar casts.[3],[4] Hairs may emerge in groups of 2 or 3. Vascular ectasias have been described.[5] Although never described earlier, dyschromic changes (pigmented globules) seen in this case have been observed in older healing lesions in majority of Indian patients, suggesting postinflammatory hyperpigmentation. This may represent the quintessential difference between dermoscopic features of cutaneous conditions in darker versus lighter skin types.[6] [Table 1] details the dermoscopic differentiation of KP from its close clinical simulators.[3],[4],[7],[8],[9],[10]{Table 1}

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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