What should you know about bacteria causing cellulitis?

These bacteria can live harmlessly on skin or in the nose, but they may cause infection after crossing the skin barrier. The exact species is often not identified because cellulitis affects deeper tissue and there may be no pus to sample.

Entry points can include small cuts, insect bites, surgical wounds, ulcers, eczema-related cracks or splits between the toes from athlete's foot. Swelling that stretches the skin and reduced skin sensation can also make unnoticed injuries easier to miss. Sometimes the opening is too small to see.

Cellulitis commonly presents with an expanding area of redness, warmth, swelling and tenderness, usually on one side of the body. Fever, chills or feeling unwell can accompany a more active infection. It is not contagious through ordinary contact, although an open wound should be kept clean and covered.

Arrange a medical assessment promptly because cellulitis generally requires prescription antibiotics. A clinician chooses treatment according to the affected site, severity, allergies, recent wounds and whether there is an abscess or another source that needs attention. Take the medicine exactly as directed and do not use leftover antibiotics.

Rest the affected area, elevate a swollen limb when practical and drink fluids unless you have been told to restrict them. Keep any wound gently cleaned and covered. Do not squeeze, puncture or vigorously massage the area. Follow the clinician's instructions if redness continues spreading or symptoms do not begin to settle after treatment starts.

Seek urgent medical care for rapidly spreading redness or swelling, severe or worsening pain, high fever, shaking chills, confusion, unusual drowsiness, dizziness, fast breathing, a racing heartbeat, purple or black skin, blisters, or red streaks extending from the area. These features can signal a deep, fast-moving infection or sepsis.

Prompt assessment is also appropriate when the affected area is around an eye, when an immune condition or immune-suppressing medicine is involved, or when diabetes, poor circulation or persistent limb swelling may complicate healing.

Ask what skin break may have allowed bacteria in, whether a wound or abscess needs separate care, how to monitor the edge of the redness, and which changes should trigger reassessment. If cellulitis has happened before, discuss treating cracked skin, athlete's foot, eczema or ongoing swelling to reduce future entry points.