Prevalence of acne rosacea in a rheumatic skin disease subspecialty clinic.

There are many causes of malar erythema besides the classic butterfly rash of acute cutaneous lupus erythematosus (LE). Twenty-one patients (6.7% of new patient visits) referred to a dermatology department-based rheumatic skin disease subspecialty clinic over a 5-year period in whom a diagnosis of cutaneous LE had been entertained were found to have diagnoses other than autoimmune connective tissue diseases. Sixteen of the patients in this cohort (76%) had acne rosacea (rosacea), while the remaining five had other dermatologic disorders. Review of their records revealed that upon referral nine of these 21 patients (43%) had positive antinuclear antibody (ANA) assays, most with insignificant or marginal titers by our laboratory standards. On repeat ANA testing in our laboratory, all of these patients had insignificant ANA titers. Physicians may be giving too much weight to low-titer ANAs in assessing patients with isolated malar erythema. These issues are discussed in the overall context of the differential diagnosis of malar erythema. A simple punch skin biopsy can be very helpful in distinguishing cutaneous LE from other causes of malar erythema.