Mosquito Bite Allergy: Understanding Skeeter Syndrome

Is It Skeeter Syndrome?

For people with a mosquito bite allergy, also known as "skeeter syndrome," symptoms are more severe than the itchy red bump of a mosquito bite. They can include a rash, large areas of excessive swelling, and even bruising that lasts for several days.

The inflammatory reaction of skeeter syndrome is pretty rare. For those who are allergic to mosquitoes, however, it can have a big impact on their ability to enjoy the outdoors. Intense itching (pruritis) can even end up causing a skin infection.

This article will help you learn to tell the difference between a normal mosquito bite and skeeter syndrome. It will also explain how skeeter syndrome is diagnosed and treated, and why you may need to see a healthcare provider.

An illustration with information about symptoms of a mosquito bite allergy

Illustration by Jessica Olah for Verywell Health

Normal Mosquito Bite vs. Skeeter Syndrome

A normal reaction to a mosquito bite looks different from skeeter syndrome. Skeeter syndrome produces much more severe symptoms.

Normal Mosquito Bite

Most people have a variety of responses to mosquito bites. The symptoms may even change over time. For example, they may happen less often if you are bitten many times over many years.

These reactions can include:

  • Immediate or delayed swelling
  • Itch around the bite area
  • Bleeding or oozing if scratched

If you have these reactions, you probably don't have a mosquito bite allergy. The term "allergy" is reserved for people with more severe or unusual responses.

Skeeter Syndrome

An allergic reaction to a mosquito bite looks like:

These reactions tend to occur in the first few hours after the bite.

Some people have vast areas of swelling after a mosquito bite. For example, the swelling might include most of an arm or leg.

Mosquito bites can also become infected, typically because of scratching to ease discomfort. Signs of infection include redness and warmth at the bite site. If you have any of these symptoms, see a healthcare provider.

Skeeter syndrome itself isn't life-threatening and does not cause long-term problems, but a skin infection should be dealt with promptly.

Anaphylaxis, the most severe type of allergic reaction, is a very rare reaction to a mosquito bite. It requires immediate medical attention. Symptoms of anaphylaxis may include trouble breathing, swelling of the tongue, lips or throat, hives, and feeling faint.

These severe mosquito bite allergy symptoms typically occur within minutes after a mosquito bite, but they can take hours to appear.

What Causes Skeeter Syndrome?

When the mosquito feeds, it pierces your skin with its needle-like proboscis and injects saliva. If you have skeeter syndrome, your body incorrectly views proteins in that saliva as harmful and the immune system responds in kind, resulting in an allergic reaction.

The hypersensitivity of skeeter syndrome relies on an immune response that involves the Immunoglobulin E (IgE) and Immunoglobulin G (IgG) antibodies in your body.

Some studies show evidence for a separate type of hypersensitivity to mosquito bites. Unlike skeeter syndrome, this response is associated with IgE but also changes in natural killer cells (rapid immune response lymphocytes) and the presence of the Epstein Barr virus and related cell disorders. Severe allergic symptoms occur but can progress into diseases for which treatment is difficult.

Who Is at Risk for Skeeter Syndrome?

You're obviously more at risk for a bite if you're in an environment that is conducive to mosquito breeding. This happens once temperatures are regularly above 50 and usually 70 degrees.

Females seek blood meal sources in order to produce eggs. The warmer and wetter the area, the more active the mosquitoes, but they also find human targets through body odors and exhaled carbon dioxide.

Those who may be at higher risk for an allergic reaction to a mosquito bite include:

  • People who work outside or frequently exercise outdoors
  • Young children
  • People not previously exposed to the local mosquito type
  • People who are immunocompromised, such as those with HIV or cancer

Difference Between Skeeter Syndrome and Skin Infection

Skeeter syndrome response usually occurs within an hour of a mosquito bite. Instead of the normal mosquito bite, a round wheal or welt between 2 and 10 millimeters (mm) occurs with skin redness peaking within 30 minutes.

People with a mosquito allergy usually will see a bite that's 5 mm or more in size. This bite can lead to a large area of inflammation that's similar to cellulitis, a bacterial infection that can arise from insect bites but typically takes much longer to develop. So do most infections, which can occur as a result of the wound (scratching, for example) or due to an illness transmitted by the mosquito itself (like Zika).

The differences also become clear when comparing responses to treatment. Cellulitis is typically treated with antibiotics, for example. Allergy symptoms from skeeter syndrome are treated with antihistamines, corticosteroids, and other interventions.

Biting mosquitoes.
Getty Images/Photographer's Choice/Roger Eritja

Diagnosing Mosquito Bite Allergy

If you have had a severe reaction to a mosquito bite it is important to see an allergist, a doctor who specializes in allergic conditions like this. Your primary care provider can help with a referral.

Diagnosing a mosquito bite allergy is based on a positive skin test, or radioallergosorbent test (RAST). This test purposefully exposes you to an extract made from the bodies of mosquitoes to see if you have a reaction. However, mosquito bite allergy testing can only identify 30% to 50% of true mosquito bite allergies.

Other tests may be needed to rule out other possible causes of your symptoms, or to identify a different type of mosquito bite hypersensitivity (for example, linked to Epstein Barr infection or Wells syndrome, another type of cellulitis that may be linked to mosquito bite exposure).

If you are diagnosed with a mosquito bite allergy, your allergist can develop a treatment plan and/or prescribe medication that can protect you in the event of an anaphylactic reaction.

Testing is only considered necessary for people who have a history of severe reactions. People who get the typical small, red, itchy bumps after being bitten by a mosquito do not need a test.

How Is Skeeter Syndrome Treated?

Treatment for an allergic reaction to a mosquito bite is focused on treating the bothersome symptoms of local reactions and, if applicable, working to mitigate the potential for and extent of severe reactions.

It also involves establishing a plan to treat life-threatening body-wide reactions, should they occur.

At-Home Treatments for Mosquito Bites

A local reaction is confined to one part of the body, so elevating the body part can help to reduce swelling. Other ways to treat a localized reaction at home include:

  • Topical corticosteroids like hydrocortisone cream
  • Oral antihistamines
  • Leukotriene modifiers like Singulair (montelukast)
  • Applying ice or cold compresses to reduce swelling and redness, and soothe the itch
  • Applying baking soda, echinacea, or other remedies to reduce itching and swelling
  • Calamine lotion to help soothe the itch

When taken before a bite, Zyrtec (cetirizine) has been shown to reduce local reactions to mosquito bites. Similarly, daily Claritin (loratadine) may help reduce reactions in children.

Taking one of these medications every day during prime mosquito months may help people with skeeter syndrome. However, any medication can have side effects, so be sure to ask your healthcare provider before you decide to try this.

Pregnant people with skeeter syndrome should take care to avoid mosquito bites. This is because not all over-the-counter (OTC) remedies are safe for use during pregnancy. Always discuss your options with your healthcare provider.

Allergy Shots

Severe cases of skeeter syndrome may benefit from immunotherapy, a form of allergy treatment where you receive shots containing small amounts of the allergen.

The goal of this treatment is to help your body get used to the allergen so you'll no longer be sensitive to it. Over time, it can improve your symptoms.

There is some evidence that allergy shots may reduce severe reactions to mosquito bites. However, at this time, options like Xolair (omalizumab) are not a widely accepted treatment for any type of mosquito bite allergy. The research is limited and the treatment isn't standardized.

Epinephrine for Anaphylaxis

Your practitioner may recommend carrying an EpiPen, which contains a manmade version of the stress hormone epinephrine.

Healthcare providers often prescribe this injectable medication for people who have a history of severe allergies. When given, epinephrine can stop symptoms of anaphylaxis.

Always call 911 after using an EpiPen. Emergency medical personnel will decide if you need a second dose.

Preventing Mosquito Bites

Preventing mosquito bites is the best strategy for those with mosquito bite allergies.

When you are planning to be outdoors, consider the following measures:

  • Try not to be outside at dusk or dawn, when mosquitoes are most active.
  • Avoid swampy and tall grassy areas.
  • Remove or treat areas of standing water (e.g., birdbaths, buckets, backyard ponds).
  • Wear long-sleeved shirts and pants.
  • Avoid wearing perfumes and scented lotions.
  • Treat clothing, camping tents, and other fabric with the insecticide permethrin (do not apply directly to the skin).
  • Limit strenuous exercise and sweating during peak mosquito times.

Insect Repellants to Protect Against Mosquito Bites

Use a mosquito-repellant containing DEET (N, N-dimethyl-3-methyl-benzamide). DEET can be safely used in concentrations of 10% to 30% on children older than 2 months of age.

However, while DEET is considered the gold standard for safe and effective use and will work for about five hours, some experts discourage its use in children under 2 years. It is considered safe for pregnant people. Other products used or under study include:

  • Picaridin (sometimes used in kids' products)
  • Permethrin (also used to treat lice infections)
  • Thiamine hydrochloride (vitamin B1)
  • Oil of lemon eucalyptus
  • Citronella

Note that repellents can cause side effects, including eye irritation, dry skin, rash, and possible allergic reaction. Use the lowest concentration that works for you and reapply as needed.

A Skeeter Syndrome Vaccine

There's not yet a way for people at risk of skeeter syndrome to prevent it through a vaccine. Scientists are, however, working to develop what they call the first vaccine-type immunotherapy to work against mosquito bite allergies.

Summary

An allergy to mosquito bites is called "skeeter syndrome." If you have skeeter syndrome, you may experience blistering rashes, bruising, and large areas of swelling. In addition, some people may develop anaphylaxis, the most severe type of allergic reaction.

You can treat mosquito allergies at home with antihistamines and topical creams. People with skeeter syndrome should also avoid mosquito-infested areas, wear long sleeves and repellent, and avoid activities like exercise that may attract mosquitoes.

Frequently Asked Questions

  • What blood type do mosquitoes like?

    Studies have found that mosquitoes prefer to feed on people with type O blood. The reasons for this are unclear. Blood type doesn't seem to affect how many eggs a female can lay.

  • Can mosquitoes bite through clothes?

    Yes. Mosquitoes can bite through thin fabric and skin-tight fabric, including T-shirt fabric, leggings, and sometimes even denim. Loose-knit sweaters also don't offer much protection.

  • What does skeeter syndrome look like?

    People with skeeter syndrome usually have extreme itching and swelling. The swelling may affect an entire limb. There may also be blisters that ooze. Sometimes the person's eyes will swell shut.

16 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Daniel More, MD
Daniel More, MD, is a board-certified allergist and clinical immunologist. He is an assistant clinical professor at the University of California, San Francisco School of Medicine and formerly practiced at Central Coast Allergy and Asthma in Salinas, California.