[Bacterial acute non necrosing cellulitis (erysipelas) in adult]

Erysipelas is defined by a sudden onset (with fever) preceding the appearance of a painful, infiltrated, erythematous plaque, accompanied by regional lymphadenopathy. It is usually localized on the lower limbs, but it can occur on the face. It is due to β-hemolytic streptococcus A and more rarely to staphylococcus aureus. It is important to establish the diagnosis and eliminate the non-bacterial causes of inflammatory edema. The other diagnoses frequently found are contact eczema, acute arthritis, bursitis, inflammatory flare-up of chronic dermohypodermitis of venous origin, flare-up of chronic multifactorial eczema (venous insufficiency, vitamin deficiencies, senile xerosis and/or contact eczema), rare familial periodic fevers, rare neutrophilic dermatoses or eosinophilic cellulitis. It is necessary to identify signs of severity that would justify hospitalization. In front of a typical acute bacterial dermohypodermitis and in the absence of comorbidity, no additional investigation is necessary. Systematic blood cultures have low profitability. Locoregional causes must be identified in order to limit the risk of recurrence which remains the most frequent complication. In uncomplicated erysipelas, amoxicillin is the gold standard; treatment with oral antibiotic therapy is possible if there is no sign of severity or co-morbidity (diabetes, arteritis, cirrhosis, immune deficiency) or an unfavorable social context. In case of allergy to penicillin, pristinamycin or clindamycin should be prescribed. Prophylactic antibiotic therapy with delayed penicillin is recommended in the event of recurrent erysipelas.