F rom time to time, I’m sure that even the most experienced dermatologist has been stumped by a case he or she thought was acne but wasn’t. So, to help differentiate acne from acne imposters, I’ve put together some illustrative cases depicting conditions that mimic acne. In addition, I’ve included advice for managing these cases. Pyoderma Faciale Also called rosacea fulminans, pyoderma faciale, is acute in onset and affects young to middle-aged women with either no prior skin complaints or with mild rosacea. Pyoderma faciale is characterized by large erythematous papules, pustules and nodules. Comedones are absent. The truncal skin is uninvolved and there are no systemic symptoms. How to Treat the Condition Systemic corticosteroids are first-line therapy and should be continued for at least one month prior to initiation of isotretinoin. A standard course of isotretinoin (total dose of 120-150mg/kg) is recommended. The corticosteroid should be continued and the dose gradually tapered throughout the course of treatment. Perioral Dermatitis Perioral dermatitis is a common dermatoses of young to middle-aged women. Periorificial erythema with dry, scaly skin and inflammatory papules is characteristic. There’s a classic sparing of the skin at the vermilion border. Perioral dermatitis and adult female acne both have a predilection for the lower face and chin. However, comedones are present only in acne vulgaris and their presence can help differentiate these two conditions. Perioral dermatitis may also be associated with itching, burning or stinging, symptoms not associated with acne vulgaris. The etiology of perioral dermatitis is unknown. The use of high-potency topical steroids on the face is a common triggering factor. How to Treat the Condition Treatment with systemic and topical anti-inflammatory antibiotics is standard, with the systemic tetracyclines being first-line therapy. The same medications may be used to treat perioral dermatitis and acne, but perioral dermatitis usually responds faster to therapy with clearing in 2 months for most patients. Lupus Miliaris Disseminata Facei Lupus miliaris disseminata facei is likely a variant of granulomatous rosacea. It presents clinically with skin-colored to slightly red/brown papules in a periorbital distribution. Lesions may also be identified more diffusely on the face. There are no comedones and no pustules present and erythema is not prominent. Granulomas with caseation necrosis is seen on histologic examination but no association with tuberculosis has been confirmed. Lupus miliaris disseminata facei is self-limited, traditionally resolving spontaneously within 2 years. How to Treat the Condition Treatment with tetracycline antibiotics or isotretinoin may hasten resolution. Scarring isn’t uncommon. Pityrosporum Folliculitis (Malassezia Folliculitis) Pityrosporum folliculitis on the chest and back can mimic truncal acne vulgaris. Follicular inflammatory papules and pustules are readily apparent. There are no comedones or nodules present and the lesions may be pruritic. KOH examination reveals yeast and hyphal forms of Malassezia furfur, but biopsy is necessary in order to identify the presence of yeast in the follicle. How to Treat the Condition Topical treatment with selenium sulfide or azole agents may be effective. If topical treatment fails, systemic itraconazole or ketoconazole may be utilized. Demodex Folliculitis Demodex folliculorum mites are commonly present on normal skin biopsy but may cause an inflammatory response and folliculitis in some cases. Demodex folliculitis affects a slightly older population than acne vulgaris. Erythematous follicular papules and pustules present on the face near the hairline and are often unilateral and pruritic. Comedones are absent. How to Treat the Condition Topical metronidazole or permethrin is effective. Syringomas Syringomas are skin-colored, dome-shaped papules in a symmetrical distribution on the face and trunk. They are more common in women than men. Eruptive syringomas develop abruptly at puberty and are most commonly located on the chest and abdomen. The location of the lesions and the time of onset may mimic acne vulgaris. However, on closer inspection the lesions are not follicularly-centered and comedones, pustules and inflammation are absent. How to Treat the Condition First-line therapies include surgical excision, snip excision and secondary intention healing, electrocautery, intralesional electrodesiccation and ablation with the CO2 or erbium:YAG laser. Dermabrasion and cryotherapy are other treatment options. Sarcoidosis Cutaneous sarcoidosis has many presentations and can mimic a myriad of skin conditions. Facial, papular sarcoid can certainly mimic acne vulgaris. Papular sarcoid is characterized by small, skin-colored to slightly yellow papules on the face with a predilection for the periorificial skin. The yellow-brown to violaceous hue of the lesions is characteristic for sarcoid. This characteristic, in combination with the lack of comedones and pustules, helps to differentiate the disease from other common facial eruptions. Biopsy is necessary to confirm the diagnosis and shows typical non-caseating granulomas. How to Treat the Condition Topical or systemic steroids are first-line treatment for cutaneous sarcoidosis. Other potential treatments include hydroxychloroquine, methotrexate, and tetracycline antibiotics.