Step 1: A symmetric red rash hugging both cheeks and spanning the nasal bridge in a butterfly shape is the textbook face of systemic lupus.
Step 2: This eruption is photosensitive and appears in the majority of lupus patients, often alongside mucosal ulcers and patchy or diffuse hair loss in roughly half of cases.
Step 3: The discoid form is different: it produces coin-shaped scaly plaques that scar and pigment, so it would not paint a smooth malar band across the face.
Step 4: A purely sun-triggered itchy bumpy rash suggests polymorphous light eruption, while chronic granulomatous skin nodules suggest cutaneous tuberculosis, so neither fits the picture.
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