Erysipelas
Other namesIgnis sacer, holy fire, St. Anthony's fire
Facial erysipelas.jpg
Erysipelas of the face due to invasive Streptococcus
Pronunciation
SpecialtyDermatology, Infectious disease

Erysipelas is a relatively common bacterial infection of the superficial layer of the skin (upper dermis), extending to the superficial lymphatic vessels within the skin, characterized by a raised, well-defined, tender, bright red rash, typically on the face or legs, but which can occur anywhere on the skin. It is a form of cellulitis and is potentially serious.[1][2][3]

Erysipelas is usually caused by the bacteria Streptococcus pyogenes, also known as group A β-hemolytic streptococci, through a break in the skin such as from scratches or an insect bite. It is more superficial than cellulitis, and is typically more raised and demarcated.[4] The term is from Greek ἐρυσίπελας (erysípelas), meaning "red skin".[5]

In animals, erysipelas is a disease caused by infection with the bacterium Erysipelothrix rhusiopathiae. The disease caused in animals is called Diamond Skin Disease, which occurs especially in pigs. Heart valves and skin are affected. Erysipelothrix rhusiopathiae can also infect humans, but in that case, the infection is known as erysipeloid.

Signs and symptoms

Symptoms often occur suddenly. Affected individuals may develop a fever, shivering, chills, fatigue, headaches, vomiting and be generally unwell within 48 hours of the initial infection.[1][2] The red plaque enlarges rapidly and has a sharply demarcated, raised edge.[4][6] It may appear swollen, feel firm, warm and tender to touch and may have a consistency similar to orange peel.[2] Pain may be extreme.[6]

More severe infections can result in vesicles (pox or insect bite-like marks), blisters, and petechiae (small purple or red spots), with possible skin necrosis (death).[6] Lymph nodes may be swollen, and lymphedema may occur. Occasionally, a red streak extending to the lymph node can be seen.[7]

The infection may occur on any part of the skin, including the face, arms, fingers, legs and toes; it tends to favour the extremities.[1] The umbilical stump and sites of lymphoedema are also common sites affected.[6]

Fat tissue and facial areas, typically around the eyes, ears, and cheeks, are most susceptible to infection.[8] Repeated infection of the extremities can lead to chronic swelling (lymphoedema).[2]

Cause

Streptococcus pyogenes

Most cases of erysipelas are due to Streptococcus pyogenes, also known as group A β-hemolytic streptococci, less commonly by group C or G streptococci and rarely due to Staphylococcus aureus. Newborns may contract erysipelas due to Streptococcus agalactiae, also known as group B streptococcus or GBS.[6]

The infecting bacteria can enter the skin through minor trauma, human, insect or animal bites, surgical incisions, ulcers, burns and abrasions. There may be underlying eczema, athlete's foot, and it can originate from streptococci bacteria in the subject's own nasal passages or ear.[6]

The rash is due to an exotoxin, not the Streptococcus bacteria, and is found in areas where no symptoms are present; e.g., the infection may be in the nasopharynx, but the rash is found usually on the epidermis and superficial lymphatics.[9]

Diagnosis

Erysipelas is usually diagnosed by the clinician looking at the characteristic well-demarcated rash following a history of injury or recognition of one of the risk factors.[2]

Tests, if performed, may show a high white cell count, raised CRP or positive blood culture identifying the organism.[2]

Erysipelas must be differentiated from herpes zoster, angioedema, contact dermatitis, erythema chronicum migrans of early Lyme disease, gout, septic arthritis, septic bursitis, vasculitis, allergic reaction to an insect bite, acute drug reaction, deep venous thrombosis and diffuse inflammatory carcinoma of the breast.[10]

Differentiating from cellulitis

Erysipelas can be distinguished from cellulitis by two particular features; its raised advancing edge and its sharp borders. The redness in cellulitis is not raised and its border is relatively indistinct.[6] Bright redness of erysipelas has been described as a third differentiating feature.[11]

Erysipelas does not affect subcutaneous tissue. It does not release pus, only serum or serous fluid. Subcutaneous edema may lead the physician to misdiagnose it as cellulitis.[12][clarification needed]

Treatment

Depending on the severity, treatment involves either oral or intravenous antibiotics, using penicillins, clindamycin, or erythromycin. While illness symptoms resolve in a day or two, the skin may take weeks to return to normal. The FDA approved 4 antibiotics--omadacycline (Nuzyra),[13] oritavancin (Orbactiv), dalbavancin (Dalvance), and tedizolid (Sivextro)--for the treatment of acute bacterial skin and skin structure infections. Because of the risk of reinfection, prophylactic antibiotics are sometimes used after resolution of the initial condition.[2]

Prognosis

The disease prognosis includes: