Dermatology: Practical and Conceptual Image Letter | Dermatol Pract Concept. 2024;14(1):e2024033 1 Lupus Panniculitis With Linear Hair Loss on the Scalp Yu-Ju Chou1, Po-Huan Ko1, Kuo-Hsien Wang1, Hua-Ching Chang1,2,3 1 Department of Dermatology, Taipei Medical University Hospital, Taipei, Taiwan 2 Department of Dermatology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan 3 Research Center of Big Data and Meta-Analysis, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan Citation: Chou YJ, Ko PH, Wang KH, Chang HC. Lupus Panniculitis With Linear Hair Loss on the Scalp. Dermatol Pract Concept. 2024;14(1):e2024033. DOI: https://doi.org/10.5826/dpc.1401a33 Accepted: July 15, 2023; Published: January 2024 Copyright: ©2024 Chou et al. This is an open-access article distributed under the terms of the Creative Commons Attribution- NonCommercial License (BY-NC-4.0), https://creativecommons.org/licenses/by-nc/4.0/, which permits unrestricted noncommercial use, distribution, and reproduction in any medium, provided the original authors and source are credited. Funding: None. Competing Interests: None. Authorship: All authors have contributed significantly to this publication. Corresponding Author: Hua-Ching Chang, Department of Dermatology, Taipei Medical University Hospital, No. 252, Wuxing St, Xinyi District, Taipei City, 110, Taiwan. Tel: 886-2-27372181 ext 8285; E-mail: b101095089@tmu.edu.tw Case Presentation A 30-year-old Asian healthy man presented with 1.5 years of asymptomatic progressive linear hair loss, which was 20 cm in length and 1.5 cm in width along the right frontal, left parietal, and left occipital scalp (Figure 1, A-D). Histopa- thology from an incisional biopsy on the left parietal scalp revealed heavy lympho-histiocytic infiltrates over superficial and deep perivascular, peri-eccrine, and perifollicular areas, and lobular subcutaneous fat necrosis (Figure 1, E-F). Alcian blue stain revealed increased mucin deposition extending from the dermis to the subcutaneous tissue (Figure 1G). The infiltrative cells in the dermis consisted mainly of CD4+T lymphocytes and CD123, the plasmacytoid dendritic cell marker, was also positive. Although no direct immunofluo- rescence was done, the serum antinuclear antibody was neg- ative. These findings were consistent with lupus panniculitis. Teaching Point Linear lupus erythematosus panniculitis of the scalp is a rare manifestation of cutaneous lupus erythematosus [1,2]. The mean age of onset is between 20 and 30  years of age, and no specific sex predominance has been noted. Most reported patients are of Asian ethnicity. The dis- ease can affect all regions of the scalp, but the parietal scalp is the most commonly affected site [1]. The pro- posed mechanism for the linear distribution of hair loss is attributed to genetically programmed clones of cells along Blaschko’s lines from early embryogenesis [2]. A hydroxychloroquine-containing regimen is the main treat- ment applied in previously reported cases, and improve- ment could be achieved in approximately 60% of cases in a mean duration of 8 weeks [1,2]. 2 Image Letter | Dermatol Pract Concept. 2024;14(1):e2024033 References 1. Lueangarun S, Subpayasarn U, Tempark T. Distinctive lupus panniculitis of scalp with linear alopecia along Blaschko’s lines: a review of the literature. Int J Dermatol. 2019;58(2):144-150. DOI: 10.1111/ijd.14155. PMID: 30074627. 2. Udompanich S, Chanprapaph K, Suchonwanit P. Linear and An- nular Lupus Panniculitis of the Scalp: Case Report with Empha- sis on Trichoscopic Findings and Review of the Literature. Case Rep Dermatol. 2019;11(2):157-165. DOI: 10.1159/000500848. PMID: 31543767. PMCID: PMC6738250. Figure 1. Linear nonscarring alopecia along the right frontal scalp, left parietal scalp (A), and left occipital scalp (B,C). (D) One erythematous indurated plaque extending from the frontal hairline on right forehead. A skin incisional biopsy showed perifollicular and perieccrine lympho-histiocytic in- flammation in the dermis (E; H&E, 50X) with subcutaneous fat necrosis (F; H&E, 250X). Increased mucin deposition in the dermis and subcutaneous fat (G; Alcian blue staining, 50X). Scale bar: 100 or 500 μm as indicated in the figures.