Assessing a patient with a red face is a common challenge for physicians. The main differential is between rosacea and other photosensitive conditions, like lupus erythematosus. It can be difficult on clinical grounds, as both may worsen with sunlight, but there are some clues that may be helpful. Rosacea has a central location in the face, including the nose. The characteristic triad of features consists of: *erythema with undefined borders; *small, dilated blood vessels (telangiectasia); *acne lesions within the redness. Spicy food and alcohol can also deepen the redness, and the condition can be itchy at times. Lupus and its variants may present in two patterns: *acute lupus: a diffuse, pink-blue hue with puffy eyelids; *cutaneous discoid lupus: discrete, thickened, scaly violaceous plaques on the face and frequently the concha of the ears. A skin biopsy can tell the difference, but many physicians aren't comfortable with this procedure. Serology for antinuclear antibodies (ANA) is helpful if the results are positive and show a homogenous pattern. A positive ANA in a speckled pattern, however, isn't significant. Finding anti-double-stranded DNA antibodies would confirm the diagnosis. It's also important to look for other signs of lupus, such as arthritis, mouth ulcers, pleurisy, hemolytic anemia and neurologic symptoms. GS