A retrospective study of clinical and histopathological characteristics in patients with pityriasis lichenoides: A comparative analysis of pediatric and adult cases

Pityriasis lichenoides (PL) is a rare inflammatory skin disorder of unknown etiology, comprising a spectrum of 2 clinical variants: pityriasis lichenoides chronica and pityriasis lichenoides et varioliformis acuta. Due to its rarity, data on its clinical and histopathological features (particularly age-related differences) remain limited. This retrospective, cross-sectional study included patients diagnosed with PL between January 2019 and January 2024 at a tertiary dermatology clinic. Demographic data, clinical presentation, histopathological subtype, treatment modalities, and disease outcomes were collected. Patients were stratified into pediatric (<18 years) and adult (≥18 years) groups for comparative analysis. A total of 41 patients were evaluated (29 adults, 12 children). The majority were diagnosed with pityriasis lichenoides chronica (80.5%). Erythema, scaling, and papules/plaques were the most common dermatological findings. Papular lesions were significantly more frequent in adults ( P = .024), while hypopigmentation was observed exclusively in children ( P = .024). No significant differences were noted between the 2 groups in terms of lesion distribution, histopathological subtype, or disease severity. During follow-up, 23 patients (56.1%) were lost to follow-up. Among the remaining patients, complete or partial remission was achieved in 14 patients, while 2 patients had persistent disease and 2 experienced relapse, with no significant outcome differences between pediatric and adult groups. This study highlights age-related differences in the clinical presentation of PL, particularly the exclusive presence of hypopigmentation in children and papular predominance in adults. Despite these clinical distinctions, histopathological patterns and overall disease severity did not significantly differ between age groups. Larger prospective studies are needed to further explore age-related variations and treatment responses in PL.