An Overview of Erysipelas (St. Anthony's Fire)

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Erysipelas is a bacterial infection of the skin that typically involves the lymphatic system. Erysipelas is also known as St. Anthony's Fire, an accurate description given the rash's fiery intensity.

Prior to the introduction of antibiotics, erysipelas was a much-feared disease, especially in infants. It was identified far back as the 11th century, where it and a cluster of other diseases were collectively named after Saint Anthony, the patron saint of lost causes.

Symptoms

Erysipelas used to be found primarily on the face. However, it is now being seen commonly on the lower extremities. This is due to the prevalence of group A Streptococcus as opposed to the type that causes facial infection (Streptococcus pyogenes).

A range of symptoms typically precede the appearance of the rash by anywhere from four to 48 hours and can include:

  • Fever
  • Chills
  • Fatigue
  • Anorexia
  • Vomiting

The rash will appear soon after as a red, hot, shiny patch.

Erysipelas rash has clearly defined borders and has a textural consistency similar to that of an orange peel (which is referred to as "peau d'orange").

Erysipelas rash also causes:

  • Pain
  • Burning
  • Itching
  • Swelling
  • Red streaks emanating from the rash
  • Blisters (in severe cases)

Lymph nodes nearest the infection may also become swollen.

Causes

Erysipelas is most often caused by a specific type of bacteria known as group A Streptococcus. It can be caused less commonly by other types of streptococcus or staphylococcus bacteria.

Generally, a skin injury such as an abrasion, cut, or trauma allows the infection to enter into the skin. From there, it can rapidly infect and spread via the lymph vessels. Some cases of erysipelas start on intact skin and on parts of the body where the lymphatic system is obstructed.

Erysipelas is most common in infants and young children and in adults over the age of 60, but it can occur at any age.

Risk Factors

Anyone can be affected by erysipelas, however, there are certain factors that make it more likely to develop. These include:

  • Weakened immune system
  • Eczema
  • Athlete's foot
  • Venous insufficiency
  • Diabetes
  • Lymphodema (swelling of the arms or legs due to disrupted lymph flow)
  • Being overweight

Diagnosis

Erysipelas is diagnosed mainly by the appearance of the rash, as it is so distinctive. Blood tests and skin biopsies generally do not help with the diagnosis.

In the past, saline solution was sometimes injected into the edge of the rash, drawn (aspired) back out, and cultured for bacteria. This method is not used anymore as most tests are either inconclusive or result in a false negative analysis.

If the symptoms are severe enough, blood may be drawn and cultured for bacteria to rule out sepsis (a potentially life-threatening event wherein the body’s response to infection causes damage to its own tissues and organs).

Erysipelas vs. Cellulitis

Erysipelas is very similar to cellulitis, though there are some differences. Most notably, erysipelas affects the upper layers of the skin, whereas cellulitis affects the lower layers of skin as well as the tissue beneath.

Cellulitis is typically slower to develop than erysipelas. The affected skin isn't as fiery red, nor does it have markedly-defined red borders.

Treatment

Erysipelas is treated with antibiotics, which may include:

Most can be treated with oral rather than intravenous (IV) antibiotics. Any pain or discomfort can often be treated with rest, a cold compress, and elevation of the affected extremity.

However, in cases of sepsis (or where infections do not improve with oral antibiotics), IV therapy may be prescribed under hospitalization.

Even after the appropriate treatment of infection, erysipelas can recur in 18% to 30% of cases.

People who are especially susceptible to recurrence include those with a compromised immune or lymphatic system.

Because erysipelas is known the damage the lymphatic system (the system which transports immune cells through the body), the infection itself can increase the risk of recurrence. People with recurrent infections may need to be treated with a daily course of low-dose antibiotics.

A Word From Verywell

Erysipelas is a fairly common skin infection that, luckily, is easily treated in most cases and rarely leads to complications. Still, if you have symptoms of erysipelas, you should call your doctor right away. Quick treatment prevents the worsening of the condition and helps ease discomfort.

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Article Sources

  1. Kozłowska D, Myśliwiec H, Kiluk P, Baran A, Milewska AJ, Flisiak I. Clinical and epidemiological assessment of patients hospitalized for primary and recurrent erysipelas. Przegl Epidemiol. 2016;70(4):575-584.

Additional Reading

  • Maxwell-Scott H, Kandil H. Diagnosis and management of cellulitis and erysipelas. Br J Hosp Med (Lond). 2015 Aug;76(8):C114-7. doi:10.12968/hmed.2015.76.8.C114

  • Michael Y, Shaukat NM. Erysipelas. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2019 Jan-. Updated Feb 3, 2019.

  • Kirmani, N.; Woeltje, K.; and Babcock, H. The Washington Manual of Infectious Disease Subspecialty Consult. Lippincott Williams & Wilkins Publishers; 2012; ISBN 9781451113648.