People think it is a spider bite, and it almost never is

Staphylococcus aureus — staph — **is a very common germ. About one in
three people have it on their skin or in their nose**, and for most of them it
causes no problem at all.

MRSA is staph that resists several antibiotics. Anyone can carry it or be
infected by it; the risk rises with hospital or nursing home stays,
skin-to-skin contact such as contact sports, and **crowded or unhygienic
places.**

The misdiagnosis this page exists to correct

A MRSA skin infection usually starts at broken skin — a scrape or a cut —
and appears as a bump or infected area that may be:

Red · swollen · painful · warm to the touch · **full of pus or
other drainage** · accompanied by a fever

**You cannot tell by looking at the skin if it's a MRSA infection. People
sometimes confuse some MRSA skin infections with a spider bite. However,
unless you actually see the spider, the irritation is likely not a spider
bite.**

That last sentence is the most useful thing here. "Spider bite" is the
explanation people reach for when something appears on their skin overnight,
and it delays treatment for an infection that is spreading. The test is
trivial: did you see a spider? If not, it probably was not one.

What to do

• Contact your healthcare provider — **especially if there is a fever, or
  it does not improve within 48 hours**
• Do not pick at or pop the bump or sore
• Cover the area with clean, dry bandages until you are seen
• Clean your hands often

"Do not pop it" is the instruction most often ignored, and it is how a
localised infection becomes a spreading one and reaches other people.

Why it matters that it is resistant

If left untreated, MRSA can cause:

Pneumonia · bloodstream infections · surgical site infections ·
sepsis — the body's extreme response to infection — and death.

The antibiotic resistance does not make MRSA more aggressive than ordinary
staph. It makes the first treatment more likely to fail, and a treatment that
fails buys the infection time.

Who is most at risk

Athletes · daycare and school students · **military personnel in
barracks** · people receiving inpatient medical care · **people having
surgery or with medical devices implanted** · people who inject drugs

The first three are the same situation described three ways: many people, in
close physical contact, sharing surfaces.

Source: Centers for Disease Control and Prevention.