Background: A 16-year-old girl presented with multiple dusky red to brown-colored papules with centrally adherent scales scattered over the trunk and extremities (with sparing of the face), interspersed with multiple faint hypopigmented macules [Figure 1]. The lesions had started appearing three years back with gradual progression. The self-healing lesions had left the hypopigmented macules with no varioliform scars. Occasional itching was the only symptom. There was no history of eruption of crops of vesicular/hemorrhagic/crusted papules, fever, painful lymphadenopathy, or systemic symptoms.Figure 1: Clinical image of the anterior abdomen of a 16-year-old Indian girl showing scattered brown papules with adherent scales, interspersed with faint ill-defined hypopigmented areasPolarized dermoscopic examination (Escope videodermoscope, ×20) from the truncal lesions revealed yellowish-orange to light brown-colored structureless areas, with focal superficial scales, and multiple scattered dark brown-black colored granules, globules, and clods. Only a few scattered dotted and nondotted vessels could be appreciated. Focal areas of hypopigmentation were seen in the lesional periphery [Figure 2]. A clinicodermoscopic diagnosis of pityriasis lichenoides chronica (PLC) was confirmed on histopathology that revealed small mounds of parakeratosis and epidermal infiltration by lymphocytes and red blood cells (RBCs). The dermoepidermal junction showed occasional necrotic keratinocytes. Focal interface vacuolar change and sparse superficial perivascular lymphocytic infiltrate with extravasation of RBCs were seen in the papillary dermis [Figure 3]. Focal melanophages were also seen in the papillary and mid-dermis.Figure 2: Dermoscopic image from a lesion on the anterior abdomen revealing yellowish-orange to light brown-colored structureless area with focal scales, and focal areas of hypopigmentation in the lesional periphery (blue arrows). Note the paucity of vascular structures – only a few focal vessels can be appreciated. Additionally, note the multiple scattered dark brown-black granules, globules, and clods, possibly suggestive of postinflammatory hyperpigmentation, typical of darker skin types [Escope videodermoscope, polarized, ×20]Figure 3: Histopathology confirming the diagnosis of pityriasis lichenoides chronica (PLC) showing small mounds of parakeratosis and epidermal infiltration by lymphocytes and red blood cells (RBCs). The dermoepidermal junction shows occasional necrotic keratinocytes. Focal interface vacuolar change and sparse superficial perivascular lymphocytic infiltrate with extravasation of RBCs can be seen in the papillary dermis. Focal melanophages in the mid-to-upper dermis are also seen [hematoxylin and eosin, ×400]Pityriasis lichenoides (PL) constitutes a spectrum of skin disorders with acute (pityriasis lichenoides et varioliformis acuta [PLEVA]) and chronic (PLC) forms. Approximately 20% of cases occur in children.[1] The etiology of PL remains uncertain. Although inflammatory response triggered by an infection has been proposed by many, the possibility of PL representing a T-cell lymphoproliferative disorder has not been ruled out. PLEVA and PLC represent a continuous spectrum with overlap in presentation.[2] In contrast to the abrupt crops of vesicular to necrotic erythematous macules and papules accompanied with systemic symptoms are archetypical of PLEVA, lesions of PLC are milder, have a gradual onset, and heal with postinflammatory hypo- (PIHy) or hyperpigmentation (PIH). The varioliform scarring of PLEVA is, however, not seen in PLC. Dermoscopy of PLC has been detailed by Errichetti et al. in seven Caucasian patients, the most common finding being orange-yellowish structureless areas, followed by focally distributed nondotted and dotted vessels, and scattered hypopigmented areas.[3] In contrast with the dermoscopic findings of PLC seen in white skin, we observed an add-on brownish hue over the yellowish-orange areas, only a few vessels but multiple scattered dark-brown-black granules, globules, and clods. Although conjectural, we believe that these additional pigmented structures suggest post inflammatory hyperpigmention, a specific dermoscopic finding described commonly in inflammatory dermatoses in the darker skin types.[4] The difficulty in observing vascular structures may also be attributable to the predominant pigmented background. Errichetti et al. have histologically correlated the orange-yellowish structureless areas of PLC to the presence of hemosiderin degradation products stemming from extravasated RBCs, and the vascular components to dilatation of superficial dermal vessels.[3] The dermoscopic differentiation of PLC from some of its close differentials is given in Table 1.Table 1: Dermoscopic differentiation of pityriasis lichenoides chronica from important clinical differentialsDeclaration 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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Nov 9, 2021
Amira Elbendary + 6
Open Access