A MRSA skin abscess is a pocket of pus under the skin caused by methicillin-resistant Staphylococcus aureus, a germ that resists many common antibiotics. Draining the pus is the key treatment, and the germ spreads easily through skin contact and shared items.
Key symptoms
- Painful, red, swollen lump that grows over days
- Lump that feels soft or drains pus
- Often mistaken for a spider bite
- Fever or chills when the infection spreads
What you find on exam
- Warm, tender, red area with a soft fluctuant center
- Surrounding cellulitis: mark the edge of the redness
- Bedside ultrasound to confirm a pus pocket
- Vital signs to check for systemic infection
Tests
- Usually a clinical diagnosis
- Culture of the drained pus to guide antibiotics
- Blood count and blood cultures if the patient looks sick
- Glucose testing in repeated infections to look for diabetes
Treatment basics
- Incision and drainage under local anesthesia
- Antibiotics for larger abscesses, cellulitis or fever: trimethoprim-sulfamethoxazole, doxycycline or clindamycin
- IV vancomycin for severe infection
- Warm compresses and wound care teaching
- Prevent spread: hand washing, covered wound, no sharing of towels or razors
Red flags
- Fever, fast heart rate or low blood pressure
- Pain far worse than the skin findings or quickly spreading redness
- Abscess on the face near the eye or in the hand
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; CDC, Guideline for Isolation Precautions (2007) and PPE sequence. Written by Making Synapses. Making Synapses is not affiliated with these organizations.