While bites and infections can be confused, there are ways to tell them apart.
Spider bites and other insect bites can cause one or several rashes or lesions, with fluid-filled blisters calledbullae.
Although MRSA looks very similar, it typically causes multiple rashes with small, pus-filled bumps calledpustules.
Illustration by Jessica Olah for Verywell Health
This is why it is important to monitor any suspected insect bite for changes in its appearance or numbers.
It may not end up being an insect bite at all.
And if it’s MRSA, fast treatment is needed.
Appearance of Blisters
Spider bitesymptoms can vary from person to person as well as by species.
Typically, spider bites result in fluid-filled blisters (bullae) that can burst and form open ulcers.
These bumps form when the immune system sendswhite blood cellsto fight the infection.
This causesinflammation(swelling) at the site of infection and death to nearby tissues.
MRSA can mimic them as well.
Complications
Both MRSA and spider bites can lead to serious complications.
With MRSA, the concern is related to the dissemination (spread) of the infection internally.
Other issues can arise with different insects.
Most cases causeheadaches, lethargy, irritability,muscle pain,tremors, and impaired coordination.
But, in severe cases, potentially life-threatening complications can rapidly develop.
They include:
Anaphylaxis(a potentially life-threatening, whole-body allergy) can occur with spider bites.
Bug Bites
Beyond spiders, other insect bites and stings can lead to complications beyond discomfort.
If left untreated, however, MRSA can cause complications affecting multiple organ systems.
The same cannot be said for MRSA because it can be so easily spread.
Wash your hands frequently and avoid the shared use of clothing, towels, and personal care items.
Severe cases may need to be treated intravenously (by delivering the drugs into a vein).
If placed on the appropriate antibiotics, the symptoms of MRSA will usually resolve within seven to 14 days.
If you don’t, the infection may return.
Worse yet, a more resistant strain may emerge and be harder to treat.
Summary
It can be hard to tell the difference between a spider bite and MRSA.
The most important clue may be the kind of blister that forms.
MRSA blisters contain pus and spider bites contain fluid.
Eventually, MRSA boils often expand and spread.
MRSA is an antibiotic-resistant bacteria that can be found in lots of community tweaks.
If it’s not treated, it can enter the bloodstream and cause life-threatening infections.
Johns Hopkins Medicine.What Does MRSA Look Like?
Centers for Disease Control and Prevention.What is MRSA?
2018 Sep 10;10(9):365. doi: 10.3390/toxins10090365.
Icahn School of Medicine at Mount Sinai.Funnel-web spider bite.
Mohamed S, Mobayed H.Cold-induced urticaria after black ant bite anaphylaxis.Qatar Med J.
2023 Nov 19;2023(2):5. doi: 10.5339/qmj.2023.sqac.5.
2022 Sep 21;11(10):1288. doi:10.3390/antibiotics11101288.
2023 Dec;99(6):431-432. doi:10.1016/j.anpede.2023.08.005
Cedars Sinai.Spider Bites.
Nemours KidsHealth.What to Do About Spider Bites.
NHS.Insect bites and stings.
2023 Aug 2;10(8):ofad414.
National Library of Medicine.
MedlinePlus.MRSA - Also called: Methicillin-resistant Staphylococcus aureus.
