What is Skeeter Syndrome?

Skeeter syndrome is a large local reaction after a mosquito bite that can mimic an infection.

What’s your first thought if your child has a large swollen area that is hot, red, and either painful or itchy?

A child with Skeeter syndrome - a bite that quickly got red, hot, and swollen.
A child with Skeeter syndrome – a bite that quickly got red, hot, and swollen. Photo by Vincent Iannelli, MD

You’re probably thinking that this bite is infected, right? It was gone without treatment over about 48 hours.

What is Skeeter Syndrome?

While that is certainly a possibility, if the reaction occurs right after a bite or sting, it is much more likely to be an inflammatory reaction – Skeeter syndrome.

The American Academy of Allergy Asthma and Immunology defines Skeeter syndrome as an inflammatory reaction to mosquito bites.
The term Skeeter syndrome was first used in a report by Simons and Peng in 1999.

Although the American Academy of Allergy Asthma and Immunology says that Skeeter syndrome is relatively rare, spend a few minutes with a pediatrician and they will likely tell you that we see it all of the time…

“The large local reactions to mosquito bites that we have designated as skeeter syndrome occur within hours of the bites and are characterized by the cardinal signs of inflammation: swelling (tumor), heat (calor), redness (rubor), and itching/pain (dolor). By inspection and palpation, it is impossible to differentiate between inflammation caused by infection and inflammation caused by an allergic response.”

Skeeter syndrome Case Studies

These reactions can be especially impressive, and scary, for parents if they occur on a child’s eyelid or penis – as loose tissue in these areas can lead to a lot of swelling.

So how can you tell if a child has Skeeter syndrome or cellulitis, an infection that requires antibiotics?

“The reactions were initially misdiagnosed as cellulitis and investigated and treated as such, although by history they developed within hours of a mosquito bite, a time frame in which it would have been highly unlikely for an infection to develop.”

Skeeter syndrome Case Studies

Although cellulitis can mimic or look just like Skeeter syndrome, it is the timing of the reaction, very soon after the bite, that will help you and your pediatrician make an accurate diagnosis. That’s important, because the treatments for Skeeter syndrome and cellulitis are very different.

In general, kids with Skeeter syndrome only require symptomatic care, perhaps an antihistamine and topical steroid cream, while cellulitis is treated with antibiotics.

Are there any other differences between Skeeter syndrome and cellulitis?

While cellulitis will likely continue to worsen, especially if it isn’t treated with antibiotics, you can expect the redness and swelling triggered by Skeeter syndrome to start to get better after two to three days. Keep in mind that many bites and stings do worsen over the first day or two though…

What Causes Skeeter Syndrome?

The large local reaction that occurs with Skeeter syndrome is triggered by antigens in the saliva of the mosquitoes.

While these typically just cause mild local reactions in most of us, others can have severe, delayed reactions, exaggerated local reactions, or very rarely, anaphylactic reactions.

“The children with skeeter syndrome remain healthy, except for recurrent large local inflammatory reactions to mosquito bites.”

Skeeter syndrome Case Studies

So what should you do for your child with Skeeter syndrome?

For one thing, use insect repellents so that they don’t get mosquito bites. And work to control the mosquitoes around your home.

You might also give them an age appropriate dose of a second-generation H1-antihistamine such as cetirizine to prevent or treat the reaction if they do get some bites.

Are mosquitoes the only insects that cause Skeeter syndrome?

By definition, yes.

But we often see these same type of large, local reactions (LLRs) after fire ant bites, bee stings, and other bites and stings.

“There is no clear definition of LLRs. They are generally described as any induration larger than 10cm in diameter around the insect sting. The swelling can occur immediately or 6 to 12 hours after the sting and can gradually increase over 24 to 48 hours. The swelling usually subsides after 3 to 10 days. LLRs represent a late-phase immunoglobulin E (IgE)–associated inflammation.”

Pansare et al on Summer Buzz: All You Need to Know about Insect Sting Allergies

Sweat bees, very small bees, for example, are notorious for “stinging” people around their eyes and causing what looks like periorbital cellulitis, as they like to drink the salt on our sweaty skin.

Is your child’s bite or sting infected?

Just remember, even if the area is hot, red, and swollen, if it got like that within hours of a bite, then it probably isn’t infected.

“The type of clinical reaction determines the risk of allergic reactions to future stings.”

Pansare et al on Summer Buzz: All You Need to Know about Insect Sting Allergies

And also be reassured that children who only have large local reactions are very unlikely to go on to have more severe, anaphylatic type reactions in the future.

More on Insect Bites and Stings