Erysipelas is a superficial bacterial infection of the skin most often caused by beta-hemolytic group A streptococci (Streptococcus pyogenes). It involves the lymphatics of the superficial dermis. Erysipelas usually occurs in isolation and has a predilection for the extremes of age, debilitated patients, and patients with poor lymphatic drainage. Erysipelas can occur on the face but is more commonly seen on the lower extremities of adults with venous insufficiency and stasis dermatitis. In children, the scalp, face, and hands are the most common sites of involvement, although it may occur anywhere. Neonates present more commonly with rapidly spreading periumbilical erythema.

Clinically, the infection presents as a strikingly red, well-demarcated plaque that is very tender. Burning paresthesias may be present. Cutaneous findings are usually preceded by abrupt onset of fever, chills, nausea, and malaise. In neonates and infants, poor feeding, irritability, and lethargy may accompany erysipelas. Lymphadenopathy is almost always present.

Trauma to the skin is thought to be an important factor in the development of erysipelas; therefore, a concomitant dermatophyte infection, surgical incision, ulceration, insect bite, or inflammatory skin condition may provide a portal of entry for bacteria. The nasopharynx is often the reservoir in cases of facial erysipelas. Additional predisposing factors for erysipelas include diabetes, immunocompromised states, and nephrotic syndrome.

Penile erysipelas responds to treatment with antibiotics but tends to recur, causing a progressive, chronic lymphedema with permanent swelling of the penis (elephantiasis). Elephantiasis may also develop in the lower extremities from recurring bouts of erysipelas.

If not treated promptly, complications in children include meningitis, septicemia, endocarditis, toxic shock, and necrotizing fasciitis.