It looks like acne, but…

Acne is one of the commonest skin diseases that dermatologists have to treat. The diagnosis of acne is usually made from the finding of the following aspects: 1) clinical features: acne vulgaris is characterized by a mixture of non-inflamed (open and closed comedones) and inflamed (papules, pustules, nodules) lesions; 2) topography of acne lesions, which involve face, back and chest; 3) epidemiology of the disease. Although acne may affect persons of all ages, the disease is most prevalent and most severe during adolescence; 4) occurrence of scars. Scarring represents a frequent outcome of acne and can lead to lifelong concern in regarding self-esteem. Even thought the diagnosis of acne is usually readily made, acne may be confused with several diseases, which can have a similar appearance. The following acneiform disorders may represent a differential diagnostic challenge for clinicians. Drug-induced acneiform eruptions are often sudden on onset and are usually more monomorphous in their appearance than acne vulgaris. A history of drug assumption is diriment for diagnosis, while the eruption resolves spontaneously following removal of the offending agent. Rosacea occurs most commonly in adults and is clinically characterized by facial flushing and erythema of the cheeks, nose, forehead and chin. Papules and pustules can develop within the areas of erythema. Scarring does not occur. Rosacea fulminans is an explosive form of rosacea, characterized by monstrous coalescent inflammatory lesions. Comedones are notably absent. The disease resolves with no or minimal scarring. In perioral dermatitis, erythema, scaling and small papules and pustules typically occur around the mouth and on the chin. Gram-negative folliculitis is characterized by the sudden development of superficial pustules in patients who have been treated for acne with antibiotics, which are ineffective in the long run. Bacteriology reveals a wide range of Gram-negative bacteria. Follicular pyodermas may mimic acne, especially when an acne-like distribution pattern is observed. However, the absence of comedones may suggest the proper diagnosis. Demodecidosis is a persistent disease of facial follicles due to mites of the species Demodex folliculorum and Demodex species. Comedones and scars are lacking and most of patients are 50-70 years of age. Diagnosis rests on demonstration of large numbers of mites. These represent only some of the skin disorders which may be misdiagnosed as acne vulgaris. An accurate evaluation of the clinical and history clues of acne is essential in properly diagnose and treat the disease.