What is staph infection?

Staph infection, also commonly called staph, is a contagious bacterial infection that typically starts on the skin or in the nose. If staph spreads to your bloodstream, it can have severe consequences.

Common related conditions
Skin Abscess (Boil)

Causes of staph infection

Staph infections are caused by Staphylococcus aureus bacteria, which can live in your body for quite some time without causing harm. Occasionally, these bacteria may come into contact with a cut or other wound, causing an infection.

Staph infections spread easily to others via direct (skin-to-skin) infection or by touching objects and materials that have come into contact with the bacteria.

Staph infections affect more than 3 million Americans each year. Boils, food poisoning, cellulitis and toxic shock syndrome are diseases caused by Staphylococcus.

MRSA is a strain of staph most commonly found in hospital settings that is resistant to many antibiotics and more easily spreads to your bloodstream, joints and organs, causing serious health issues.

Risk factors for staph infection

Anyone can develop a staph infection. People at higher risk for developing staph include:

  • Children in daycare — children can transfer infections between each other, children in daycare are exposed to more germs and have lower immunity built up to fight the infections.
  • People with lowered immune systems — if you have cancer, diabetes or other chronic conditions that lower your immune system, you are at higher risk for developing a staph infection.
  • People who frequent communal environments — locker rooms and shared bathrooms increase the risk of coming into contact with staph bacteria.
  • Athletes — athletes who participate in sports with skin-to-skin contact (wrestling, basketball or football) are more at risk for developing a staph infection.
  • Healthcare workers or healthcare patients — people who work in a healthcare environment or patients receiving care in a hospital or other facility are at greater risk of developing staph and complications from the infection.

Symptoms of staph infection

Symptoms of staph vary from a mild skin infection to life-threatening if it gets into the blood and affects the lining of the heart. Symptoms will differ based on the severity of the infection.


Boils are the most common type of staph infection. Symptoms of staph infections caused by skin abscesses or boils include:

  • Pain and swelling at the affected area
  • Pocket of pus that develops over a hair follicle
  • Typically occurs in the groin or under the arms


  • Large blisters that could ooze fluid
  • Painful rash


Cellulitis is a skin infection in deeper layers of the skin typically caused by Staphlyococcus.

  • Redness and swelling on the surface of the skin
  • Sores or ulcers that ooze discharge (not in all cases)

Staphylococcal scalded skin syndrome

Staph infections can sometimes produce toxins that lead to staphylococcal scalded skin syndrome. This condition occurs in children and babies.

Symptoms include:

  • Fever
  • Rash
  • Blisters — when the blisters break, the top layer of skin can peal to leave a surface looking like a burn

Food poisoning

Food poisoning is often caused by staph bacteria. Symptoms of staph bacteria-induced food poisoning include:

  • Nausea
  • Vomiting
  • Diarrhea
  • Low blood pressure
  • Dehydration

Septicemia (blood poisoning)

When staph enters the blood stream, it causes septicemia. Symptoms of septicemia include:

  • Fever
  • Low blood pressure
  • Bone and muscle aches

Toxic shock syndrome

Staph bacteria are linked to toxic shock syndrome through the use of tampons. Symptoms of toxic shock syndrome include:

  • High fever
  • Nausea and vomiting
  • Diarrhea
  • Abdominal pain
  • Muscle aches
  • Rash that resembles a sunburn

Diagnosis of staph infection

Mild staph infections can be diagnosed and treated by your primary care provider, who will ask you about your symptoms and examine any skin lesions.

In most cases, your provider will take a tissue sample and send it to a laboratory to confirm staph bacteria is present. If staph is suspected but there is no skin infection, blood work will be done to confirm diagnosis.

If the infection is severe, you may be sent to the emergency room. If staph is found in the bloodstream, you will be admitted to the hospital to be treated.

Treatments for staph infection

Staph requires an antibiotic treatment, varying based on the severity of the infection. Most cases of staph infection will be treated with oral antibiotics. Occasionally, an infected skin wound will need to be drained, which can be done in your primary care provider’s office.

Staph bacteria are becoming resistant to antibiotics. Methicillin resistant Staphylococcus aureus (MRSA) strains are challenging to treat and may need IV antibiotics and require hospitalization.

Recovery from staph infection

Each case of staph infection is different, but most often staph will resolve in 1-3 weeks. Once you complete your antibiotic treatment, you’ll no longer be contagious, but you should keep any skin infection clean and covered until it is completely gone.

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