Common Skin Infections: Cellulitis, Erysipelas, Impetigo

Diagnosis

Your doctor will perform a physical examination of your skin. He or she will suspect cellulitis or erysipelas if you have a spreading, swollen, reddened, warm, and tender area of skin that developed rapidly. The area may surround a break in the skin, and you may feel ill and have chills or fever. The doctor will check for involvement of the face, which is common in erysipelas, and involvement of the legs, which is common in cellulitis. Cellulitis and erysipelas differ in that erysipelas tends to have a sharper border between affected and unaffected skin.

In some cases, doctors will try to identify the specific bacteria causing the cellulitis by taking a specimen for culture. This is often done using a needle. Punch biopsy, which takes a sample of tissue, may also help differentiate cellulitis from some other similar-appearing skin disease. If a cut is present, it may be possible to get a sample of bacteria by swabbing the wound. Laboratory tests may or may not be ordered in suspected cases of cellulitis, as most findings tend not to be specific for this infection. Blood cultures are usually done for severely ill patients.

Your doctor will suspect impetigo if you have a honey-colored crust covering a blistered rash.

Your doctor may suspect a necrotizing infection if, in addition to skin symptoms similar to those of cellulitis, you have pain that is out of proportion to the apparent size of your infection.

Low blood pressure, fast breathing, and a fast heart rate are signs of a more serious or advanced infection. In those who are suspected of having an advanced, or necrotizing cellulitis, doctors may order x-rays, a CT scan, or an MRI to better define the extent of infection. Surgery may also be necessary to cut into the infection and probe the underlying tissue in order to ensure that a serious infection is not present.

Prevention and Screening

It is important to control conditions that might make you more likely to have an outbreak of cellulitis. In particular, diabetes must be carefully controlled, and proper foot care is essential for those with this disease.

If you have swelling (edema) of the legs or arms due to a heart condition or surgery, try to follow advice to reduce the edema, and take special care of your skin and be sure to report any changes in skin color or skin erosions to your doctor.

If you have a splinter, cut, scrape, or insect bite, keep the wound clean and report any changes in the surrounding skin to your physician. Using antibiotics to prevent cellulitis is not recommended.

See your physician if you have athlete’s foot or another fungal infection that does not improve.