Spider Bites vs. MRSA Infections

See the doctor for any swollen lesion that doesn't go away

Pediatrics dermatologist with patient
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Methicillin-resistant Staphylococcus aureus (MRSA) skin infections are becoming more and more common. These MRSA lesions are sometimes confused with spider bites since they can often look the same. Learn when you should see the doctor if your child has a lesion.

Signs Common to MRSA and Spider Bites

Since spider bites and MRSA infections have very different treatments, it is important to know that they look similar and when you should see your doctor. Don't be quick to blame a lesion on a spider bite unless you actually saw a spider bite your child since that could bias your doctor's diagnosis.

A classic sign of infection with MRSA is that people will describe the area as looking like a spider bite:

  • A red, swollen, painful area on a child's skin
  • A central area that can have a crust or an area of necrosis (dead skin)

When to See the Doctor

See your pediatrician if any bite, pimple, or another rash continues to get red and swollen after a few days of home treatment. See your pediatrician right away if you suspect that your child might have an MRSA infection—a red, swollen, painful area on his skin that is full of pus or is draining.

Most pediatricians know about the MRSA and spider bites connection now, so they automatically think about MRSA when someone comes in complaining of a spider bite. Still, you don't want to delay the treatment for a resistant staph infection because you are treating a spider bite that your child never really had.

MRSA Staph Infections That Are Resistant to Antibiotics

MRSA infections are seen with increasing frequency and can affect even healthy adults and children. They were once limited to people with weak immune systems and seen mostly in patients in hospitals and nursing homes.

The CDC says anyone can get MRSA through direct contact with other people or sharing personal items.

Schools, daycares, and gyms are areas where MRSA can be spread due to the sharing of equipment and close contact with other people in those facilities. Children and adults can carry MRSA in their nose while they are healthy and have no symptoms of infection from it. The CDC says 5% of hospital patients carry MRSA on their nose or skin. As they are not sick from it and you never know who might be a carrier.

The trouble comes when MRSA causes a skin infection. It can be difficult to treat as it is resistant to the most commonly used antibiotics. While MRSA infections are sometimes limited to simple pimple-like infections, they can often become a much larger abscess or boil that needs to be drained.

Photos of Spider Bites and MRSA Infections

If you would like to see photos of spider bites and MRSA to see how similar they appear, you can visit these pages. Warning, the photos can be graphic and may be disturbing to you.

  • Spider bite photos: Classic photos of spider bites show their different presentations.
  • Photos of MRSA infections: These photos are from the CDC and show skin infections of MRSA. The CDC notes that these infections often first look like spider bites. That should be a caution to have any suspicious lesion looked at by a doctor.
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Article Sources
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  1. Cleveland Clinic. Methicillin-resistant Staphylococcus aureus (MRSA): Diagnosis and tests. Updated November 10, 2916.

  2. Centers for Disease Control and Prevention. Methicillin-resistant Staphylococcus aureus (MRSA). Updated June 26, 2019.