However, the two conditions can overlap, which can make it hard for a doctor to tell the two conditions apart.
Previously, doctors thought that erysipelas only affected the face, but the National Organization for Rare Disorders now estimate that around 80 percent of all cases occur on the legs. It can also appear on the arms and torso.
Often, a person will feel unwell before visible signs of erysipelas appear on the skin. Symptoms can include fevers, chills, shivering, and high temperature.
Erysipelas causes the skin to appear red, swollen, and shiny.
Image credit: CDC/Dr. Thomas F. Sellers/Emory University
The skin is then usually affected in a particular area and can appear in one of the following ways:
- swollen and shiny
- warm and tender to the touch
- blisters in severe cases
- sharp edges between the affected area and unaffected skin
- red streaks above the affected area
- can turn purple or black in severe cases
These signs and symptoms are often quite abrupt and can develop in just a few hours or days.
Erysipelas develops when bacteria enter the skin through cuts or sores.
Skin injuries that increase the chances of developing erysipelas include:
- cuts to the skin, ulcers, or bed sores
- insect or animal bites
- wounds from surgery
Pre-existing skin conditions that break the surface of the skin also increase the chances of getting erysipelas.
These conditions include:
Other conditions can also increase the likelihood of a person getting erysipelas. These do not always affect the skin directly, and include:
- veins and lymphatic vessels not working as they should
- poorly controlled diabetes
- circulation problems
- weakened immune system
Some medications can weaken the immune system and lead to erysipelas. These medications include some cancer drugs and medication commonly used after organ transplants.
Anyone can get erysipelas, but it most commonly affects infants and adults over the age of 60.
Erysipelas is not hereditary or contagious.
A blood test can reveal raised levels of white blood cells, which can indicate damage caused by an infection.
In general, a doctor will be able to diagnose erysipelas by the appearance and symptoms of the affected area. This is because the symptoms of erysipelas tend to occur only with this particular condition.
The person's medical history, highlighting previous injuries or surgery, will often suggest the possible cause as well.
Further testing is not usually needed.
Doctors may carry out a blood test if there are any signs of systemic infection, such as bacteria in the blood (bacteremia). However, the identification of bacteria is not always possible, even in a laboratory.
Tests can also help to reveal:
- raised levels of white blood cells, which can be caused by tissue damage and bacterial infection
- elevated levels of C-reactive protein, which is produced by the liver in increased amounts when inflammation occurs
- positive blood culture indicating a bacterial infection
- the presence of a specific infection, caused by an animal bite, for example
In some cases of deep infection, a magnetic resonance imaging (MRI) or computed tomography (CT) scan is necessary.
Treatment and recovery
Erysipelas is curable. It is important to start treatment as early as possible to limit the chance of further complications.
It is therefore essential that anyone who is allergic to penicillin tell their doctor before starting treatment so that they can prescribe other medications, such as erythromycin or cephalexin.
People with erysipelas will typically take antibiotics by mouth for between 7 and 14 days. In more severe cases, the drugs will be put directly into the skin via a drip.
Anti-inflammatory drugs, such as ibuprofen, can help relieve discomfort.
There are also other ways to help relieve pain and discomfort and speed up the healing process, such as:
- keeping the infected area elevated, although still ensuring movement to try and prevent clotting
- cooling packs placed on the skin
- lotions to stop the skin getting dry and cracking
- anti-inflammatory painkillers, such as ibuprofen
- compression stockings once the infection has settled
- treatment for any breaks in the skin, often with a prescribed cream that is applied directly
Prevention and outlook
Erysipelas is curable. Signs of a fever and illness associated with erysipelas will often disappear within a few days of starting treatment, although the skin infection can take weeks to clear up. There is no scarring.
About one third of those who receive treatment for erysipelas develop the condition again. When this happens, a long-term course of medication can be prescribed to treat it.
It is important that the person sees their doctor as early as possible if they have any concerns about repeat attacks.
If other conditions have contributed to the attack, such as eczema, athlete's foot, or diabetes, then treating those conditions properly can help prevent further outbreaks of erysipelas. Treating breaks to the skin swiftly can also help.
Likewise, if being overweight or having bad circulation contributed to the infection developing, a change in lifestyle and diet can often help limit the chances of erysipelas returning.