What MRSA looks like
Most MRSA infections begin in the skin. A small fraction become invasive and life-threatening. The earlier the pattern is recognised, the better the outcome.
Skin and soft-tissue infection
The classic presentation is a painful red bump that looks and feels like a spider bite, often warm to the touch and filling with pus. Boils, abscesses, cellulitis, folliculitis, and impetigo are all common forms. The skin around the lesion may be swollen, tender, and accompanied by fever.
Because community-associated MRSA (notably the USA300 lineage) is aggressive in healthy skin, lesions can enlarge over 24–48 hours and may require incision and drainage rather than antibiotics alone.
Invasive disease
When MRSA reaches deeper tissues or the bloodstream it can cause bacteremia, endocarditis, osteomyelitis, septic arthritis, and necrotising pneumonia. Symptoms include persistent high fever, rigors, severe localised pain, shortness of breath, or confusion.
Invasive MRSA carries a mortality rate of roughly 15–20% even with appropriate therapy and is one of the leading causes of healthcare- associated bloodstream infection in the United States.
When to seek care
Seek same-day care for any skin lesion that is rapidly enlarging, has red streaks tracking from it, is accompanied by fever, or is on the face. Seek emergency care for shortness of breath, chest pain, confusion, or signs of sepsis in someone with a recent skin infection.