A Case of Kyrle's Disease with Dermatoscopic Findings.

A 36-year-old male presented to the skin outpatient department with complaints of itchy lesions over the body for 8 months. The lesions initially began over legs and progressed to involve both lower limbs, upper limbs, and lower abdomen. He had no known comorbidities such as diabetes mellitus and hypertension, or any other chronic kidney or liver disease. His blood pressure was within normal limits. On investigation, his serum creatinine was 1.32 mg/dl, random blood sugar was 94 mg/dl, and liver function tests were normal. On examination, multiple, large, discrete, hyperpigmented, and hyperkeratotic papules with central crusted keratotic plugs were present over bilateral extremities [Figure 1a and b] and lower abdomen. No oral, scalp, and nail changes were present. Hand-held dermatoscopy done with DE-300 (Firefly) polarizing digital dermatoscope with (20×) magnification showed bright whitish to brownish scales in the center, a structureless whitish-gray area surrounding the central crusts, and peripheral brown pigmentation [Figure 2]. Biopsy taken from one of the papules over the right forearm showed hyperkeratosis, acanthosis, extrafollicular, and follicular ortho and parakeratotic plugging with epidermal invagination. The plug contained degenerated nuclear debris and few dyskeratotic squamous cells. The upper dermis showed histiocytic infiltration, vascular proliferation, and moderate mixed inflammation comprising lymphocytes, plasma cells, and few polymorphs [Figure 3]. Changes were suggestive of Kyrle's disease (KD).

Figure 1

Multiple, discrete, hyperpigmented, and hyperkeratotic papules with central crusted keratotic plugs over (a) upper limbs and (b) lower limbs

Figure 2

Dermoscopy showed whitish to brownish scales in the center (blue arrow), a structureless whitish-gray area surrounding the central crusts (red arrow) and peripheral brown pigmentation (black arrow) (DE 300 (firefly) polarized mode ×20)

Figure 3

Hyperkeratosis, acanthosis, ortho, and parakeratotic plugging with epidermal invagination. Histiocytic infiltration, vascular proliferation, and moderate mixed inflammation in the upper dermis. H and E stain (×10)

KD is characterized by the transepidermal elimination of abnormal keratin. It is classified as a subtype of acquired perforating disorders which includes KD, elastosis perforans serpiginosa, perforating folliculitis, and reactive perforating collagenosis. It is commonly seen in patients with diabetes, renal disease, and rarely in liver disease. KD should be differentiated from other primary acquired perforating disorders [Table 1].

Table 1

Differentiating features of various perforating dermatosis

The clinical diagnosis of acquired perforating dermatoses could be difficult, but recently some investigators described several useful diagnostic dermoscopic features.[12] The bright white clods in the center of the lesions correspond to a dilated infundibulum stuffed with keratin and extruded cell debris. The structure-less gray area surrounding the central white clod most probably is a consequence of the combination of epidermal changes (acanthosis, hypergranulosis, and hyperpigmentation of basal keratinocytes and pigmented inflammatory cells) and dermal changes (thickened bundles of collagen in vertical orientation).[1]

Gray and blue colors are known to be associated with melanin in the dermis and is caused by light scattering by dermal collagen inducing the Tyndall effect. It has been shown that reticular brown lines (network) are due to melanin pigment deposition along the rete ridges. Elongated rete ridges with hyperpigmentation of basal keratinocytes are seen on either side of invaginated kerarotic plug. The distribution of the lines clustered around the plug correlates to an increase in melanin pigment located in melanocytes and/or keratinocytes, following the initial inflammatory process.[2] In our patient also, three zonal concentric patterns were seen with central white clod, surrounded by structureless gray area and peripheral brown lines.

Dermoscopy is one of the non invasivemethods of diagnosing various dermatosis by revealing features that give insight into the underlying pathology. KD can also be diagnosed on the basis of specific features without biopsy. Dermoscopy also helps to differentiate between hypertrophic lichen planus (HLP), prurigo nodularis (PN), and various acquired perforating dermatosis, which were one of the differential diagnosis in our case. Dermoscopy of HLP and PN show pearly white areas which are spread over the whole periphery of the lesion giving a “starburst” appearance in PN and localized in the center with peripheral extensions in HLP along with gray-blue globules, comedone-like opening, and brownish-black globules.[3]

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.