Discoid Lupus Erythematosus: A Cross-Sectional Study From the Sindh Institute of Skin Diseases, Karachi, Pakistan.

Introduction Discoid lupus erythematosus (DLE) is the most common form of cutaneous lupus erythematosus. It is a chronic, scar-forming, photosensitive autoimmune dermatosis presenting with erythematous and scaly lesions. Predisposed areas include sun-exposed areas like the nose, forehead, and cheeks, as well as the upper body and extremities. The histological findings are typical, with interface dermatitis. Immunoglobulin M (IgM) and immunoglobulin G (IgG) are the most common deposits in the dermoepidermal junction of the involved skin. The most common treatments used are sunscreens, topical corticosteroids, and antimalarials. Immunosuppressive agents, thalidomide, dapsone, and retinoids can be used in refractory cases. The aim of this study was to study the clinicopathologic patterns of DLE in patients presenting to the Institute of Skin Diseases in Sindh, Karachi. Methods A total of 53 consecutive patients with DLE meeting the inclusion criteria were evaluated between February 18, 2018 to March 2, 2019 at the Institute of Skin Diseases. Patients with clinical suspicion of DLE were evaluated and studied prospectively after written informed consent was obtained. Information was then collected from their medical histories, physical examination records, and laboratory investigation reports. Results A total of 53 consecutive patients with clinical and/or histological diagnosis of DLE was included in this study, out of which 75.5% (40) were females with a male to female ratio of 1:3.1. The mean age of the patients at the time of presentation was 36.02 ± 10.04 years, ranging from 14 to 65 years. More than half of the patients (35, 66.0%) were under 40 years of age and 20.8% (11) had a positive family history of DLE. DLE was localized in 36 patients (67.9%) and exposure to the ultraviolet radiation (UVR) was found to be the most frequent induced factor in 46 patients (86.8%), followed by stress which was observed in 14 patients (26.4%). The distribution of commonly affected sites were the face (81.1%), the limbs (71.7%), and the scalp (48.4%) of the patients. Serology antinuclear antibody (ANA) was positive in 56.6% and serology anti-double-stranded deoxyribonucleic acid antibodies (anti-dsDNA) were positive in 45.3% of patients. Smoking, as an induced factor, was more commonly observed among male patients as compared to the female patients with a proportion of 53.8% vs. 2.5%, p < 0.001, while stress was more common among female patients with a proportion of 35% vs. 0%, p = 0.013, respectively. Histopathology with direct immunofluorescence was done in 33 cases which included cases with negative serology or where the diagnosis was in doubt clinically. The main histopathological features observed were periadnexal and perivascular dermal infiltrates, basal cells vacuolization, epidermal atrophy, hyperkeratosis, and follicular plugging. The commonest morphological form observed was the classic discoid plaque form. Conclusion Clinical patterns of DLE in our population comprises of female dominance. Exposure to UVR was the leading inducing factor. The face and limbs were the most commonly involved sites, and the majority of the patients had localized DLE with positive ANA in more than half of those patients. The importance of limiting ultraviolet radiation exposure and toxins (drugs and smoking) should be emphasized in our population.