Matsuo Maho, Iwata Hiroaki
Dermatology, Gifu University Graduate School of Medicine, Gifu, JPN.
Cureus. 2025 Aug 11;17(8):e89836. doi: 10.7759/cureus.89836. eCollection 2025 Aug.
Annular erythema is a nonspecific clinical sign arising from various conditions, including infections, cutaneous lymphomas, connective tissue diseases, and inflammatory dermatoses. Psoriasis vulgaris typically presents as sharply demarcated erythematous plaques with silvery scales; however, annular forms are rare and may complicate diagnosis. We report a nine-year-old girl with an annular erythematous lesion on the anterior chest that gradually expanded over two months, spreading to the extremities and trunk with mild pruritus. Despite suspicion of tinea corporis, repeated fungal tests were negative, and topical corticosteroids were ineffective. Skin biopsy showed marked hyperkeratosis, loss of the granular layer with parakeratosis, and subcorneal Munro's microabscesses; no fungal elements were found. Laboratory tests and imaging were unremarkable, and genetic screening for IL36RN and CARD14 found no pathogenic variants. A diagnosis of psoriasis vulgaris was made with a Psoriasis Area and Severity Index (PASI) score of 7.8. After failed topical treatment, systemic secukinumab therapy was initiated, leading to complete lesion resolution within two months. This case emphasizes the importance of considering psoriasis in the differential diagnosis of pediatric annular erythema and demonstrates the value of histopathology and biologics in managing atypical pediatric psoriasis.
环状红斑是一种由多种情况引起的非特异性临床体征，包括感染、皮肤淋巴瘤、结缔组织病和炎症性皮肤病。寻常型银屑病通常表现为边界清晰的红斑鳞屑斑块；然而，环状形态罕见且可能使诊断复杂化。我们报告一名9岁女孩，前胸出现环状红斑性病变，在两个月内逐渐扩大，蔓延至四肢和躯干，伴有轻度瘙痒。尽管怀疑为体癣，但反复真菌检测均为阴性，外用糖皮质激素治疗无效。皮肤活检显示明显角化过度、颗粒层缺失伴角化不全以及角层下Munro微脓肿；未发现真菌成分。实验室检查和影像学检查均无异常，对IL36RN和CARD14进行基因筛查未发现致病变异。诊断为寻常型银屑病，银屑病面积和严重程度指数（PASI）评分为7.8。局部治疗失败后，开始使用司库奇尤单抗进行全身治疗，两个月内皮损完全消退。该病例强调了在小儿环状红斑鉴别诊断中考虑银屑病的重要性，并证明了组织病理学和生物制剂在治疗非典型小儿银屑病中的价值。
