Discoid lupus erythematosus is commonly triggered by which factor?

• A. Sun exposure
• B. Cold exposure
• C. Fungal infection
• D. High-fat diet

Answer: (A)

Sun exposure is the trigger because discoid lupus erythematosus is photosensitive. Ultraviolet light from the sun initiates skin injury and an inflammatory immune response in predisposed individuals, leading to the chronic, scaly, erythematous plaques that appear on sun‑exposed areas such as the face, ears, and scalp. The damage from UV light promotes keratinocyte injury and exposure of autoantigens, which drives localized lupus activity and can result in scarring and pigment changes over time. That’s why protecting skin from the sun and using broad‑spectrum sunscreen helps prevent flares. Cold exposure, fungal infection, and a high-fat diet don’t have the same established link to triggering discoid lupus lesions.