What Is Skeeter Syndrome?

  • Albertina Metson Bachelor of Science - BS, Neuroscience, University of Bristol
  • Saira Loane Master's of Toxicology, Institute of Biomedical Research, University of Birmingham
  • Charlotte Mackey BSc (Hons), Psychology, University of Exeter, UK

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Skeeter syndrome is a relatively rare condition that causes severe allergic reactions to mosquito bites. People with Skeeter syndrome are allergic to substances in the mosquito’s saliva, which causes significant swelling around the bite, pain, itchiness, and sometimes fever. It can affect anyone although children, the elderly, and people with a compromised immune system are most often affected.1 

Skeeter syndrome is easily treated with antihistamines, hydrocortisone cream, and over-the-counter painkillers to ease pain and fever. It is not contagious and usually clears up within three to ten days with appropriate treatment.1 

It is important to understand the causes and symptoms of Skeeter syndrome so that sufferers can be diagnosed and take appropriate precautions. Read on to discover the symptoms, causes, diagnosis, and treatment for this disease. 


Why do mosquitoes bite us? 

Mosquitos pierce our skin with their long, needle-like mouthpiece called a proboscis. They suck blood from beneath our skin and secrete their saliva into the bloodstream. Mosquitoes carry pathogens in their saliva, which can cause diseases when we are bitten by them.2 

Only female mosquitoes bite us; they feed on our blood to gain proteins to produce their eggs. Mosquitoes detect their prey using antennae and ‘palps’ (the organs between their antennae), which sense our body odour and carbon dioxide expelled in our breath.2

Why are some people more prone to mosquito bites? 

People with a higher metabolic rate tend to attract mosquitoes more as they produce more carbon dioxide. This can occur when doing exercise, drinking alcohol, or when pregnant.2 

Research into whether certain blood types are more attractive to mosquitoes has found that mosquitoes that carry the dengue virus are more attracted to people with the O blood type.3 Other research on blood type and mosquito attraction has been inconclusive, and researchers believe that skin odour and microbiota (a person’s unique make-up of microorganisms in their body and on their skin) are more important factors in mosquito attraction.4 

Genetics is thought to be the main predictor of proneness to mosquito bites. A twin study in 2015 found that our DNA accounts for approximately 67% of mosquito attraction, which is a similar level of heritability as height and intelligence. Identical twins (who share 100% of their genes) had more similar levels of mosquito attraction than non-identical twins.5 


Histamine is a chemical produced by the immune system that signals cells to trigger blood vessels to dilate, which allows fluids from the blood to reach the allergen site. Substances in these fluids help to remove the allergen. 

When a large amount of histamine is released into the bloodstream, it can cause a range of physical effects, including increased heart rate, lowered blood pressure, and contraction of smooth muscle, especially that found in our airways, which can cause trouble breathing. In extreme cases, these effects cause anaphylactic shock, a severe and potentially life-threatening allergic reaction. 

Causes of skeeter syndrome

Mosquito bites

Proteins in mosquito saliva trigger the body’s immune response to fight it, which causes the characteristic bump and itchiness. When people are severely allergic to these proteins, Skeeter syndrome can occur, causing a much greater allergic reaction. 

The bump caused by a bite usually appears 15-30 minutes after being bitten and is known as a ‘wheal and flare6, wheal meaning the swelling caused by the release of serum (a blood component) into the body tissue, and flare meaning redness of the skin caused by dilation of the surrounding blood vessels.

Allergic reaction

Our body recognises the mosquito saliva as an allergen and triggers an immune response; histamine is sent to the site of the bite in an attempt to remove the allergen. It is the histamine that causes itchiness and swelling, rather than the substances in the mosquito saliva. 


Genetics play a key role in how prone we are to mosquito bites and therefore Skeeter syndrome.5 

Symptoms of skeeter syndrome

Itching and swelling

The first symptom to appear will be a large swelling around the bite which is itchy. The skin may feel warm. The allergic reaction causes these symptoms. 

Redness and inflammation

The skin around the bite will have an unusual colour and texture. In lighter skin tones, the skin will appear red, and in darker skin tones the skin will appear darker than usual. The skin can also feel hard. 

Pain and discomfort

For some, the swelling can be so severe that the pressure makes it painful. 


Clinical examination

A doctor will carry out a physical examination of the swelling. They will also review your medical history and ask some questions to understand when and where you were bitten, if you have had these symptoms before, and if you have travelled abroad (as mosquitoes from different regions carry different allergens). They will establish the timeline between your getting bitten and the onset of symptoms and ask if you have any other symptoms of concern, such as shortness of breath. 

Allergy testing 

Allergy testing for Skeeter syndrome involves identifying specific allergens within mosquito saliva. This test is only necessary for people who have a history of severe reactions. This can help provide valuable information for effective management. 

One way to do this is a simple skin prick test; small amounts of mosquito saliva extract or specific substances found in the saliva are injected into the skin surface (usually on the forearm or back) and the doctor will observe the skin for any signs of an allergic reaction, such as swelling, itchiness, or itching. The size of the reaction will indicate the severity of the allergy.

However, it is worth noting that mosquito bite allergy testing can only identify between 30% and 50% of true mosquito bite allergies,7 and commercially available skin prick testing for whole body mosquito allergen extract does not play a significant role in diagnosis.1 Since allergy testing alone is not definitive, it is important to consider the results alongside a clinical examination and medical history.

There's no simple blood test to detect mosquito antibodies in blood. Therefore, healthcare professionals will most likely diagnose a mosquito allergy by physical examination and taking a patient history.

Treatment and management

Over-the-counter remedies

A doctor will suggest taking oral antihistamines, using a hydrocortisone cream on the affected area, and taking painkillers such as ibuprofen to reduce pain and fever. 

Prescription medications

In severe cases, your doctor may suggest systemic corticosteroids, which can be in pill or injection format. These mimic the action of the natural stress hormone, cortisol, which helps reduce inflammation. They can also suppress the immune system, which helps to prevent the side effects caused by the action of histamine, thereby relieving symptoms.8

A doctor may also suggest that you carry epinephrine with you if you have had severe reactions to mosquito bites in the past. This is available as an autoinjector, which you can inject yourself when required.

Prevention strategies 

Fortunately, there are several steps you can take to prevent mosquito bites and therefore Skeeter syndrome: 

  • Wear clothing that covers your limbs when abroad and in the summer
  • Wear thick clothes if you can, as mosquitoes can bite through thin fabrics 
  • Avoid areas where mosquitoes reside, such as bodies of water
  • Use insect repellent. Repellents containing DEET tend to work best
  • Wash as soon as possible after exercise, as the lactic acid in sweat attracts mosquitoes9 
  • Use insect screens or nets over open doors and windows
  • Stay inside when mosquitoes are most active (dusk and dawn)
  • Use mosquito nets around your bed at night 
  • Treat clothing and tents with mosquito repellent 

At present, there is no vaccine to prevent Skeeter syndrome in at-risk individuals. However, scientists are working to develop what they call the first vaccine-type immunotherapy to work against mosquito bite allergies.10

Who is at risk?


Anyone at any age can suffer from Skeeter syndrome. Children may be more prone to Skeeter syndrome as their immune systems are still developing.1 Additionally, their smaller bodies may react more intensely to a bite, causing more pronounced symptoms. Fortunately, there is evidence that children can become desensitised to allergens in mosquito saliva as their immune system develops.7

Weakened immune system

Individuals with a compromised immune system may suffer more severe reactions to mosquito bites due to their immune system not being efficient at fighting off the allergens.

Allergy-prone individuals

People prone to allergies are more at risk of Skeeter syndrome due to their heightened immune response to foreign substances, such as the proteins found in mosquito saliva. There is also a genetic component to allergies, thus families with a history of allergies may be more susceptible to severe reactions to mosquito bites. 

Repeated exposure 

People who are frequently exposed to mosquito bites, such as people who work outside, may experience Skeeter syndrome more intensely as repeated exposure sensitises the immune system to the proteins in mosquito saliva, leading to increasingly severe reactions over time.1

Complications and risks

Secondary infections - cellulitis

Cellulitis (a bacterial skin infection) can occur a few days after the initial bite and is usually caused by picking or scratching the bite, which can break the skin, allowing bacteria to enter the body. Bacteria can also enter the skin via the opening caused by the insect bite itself. Cellulitis is commonly caused by bacteria that live underneath our nails, such as Streptococcus and Staphylococcus aureus

Cellulitis causes red, swollen, and tender skin around the bite and a fever. You may also see red streaks along the skin around the bite, puss-like fluid weeping from the bite, blisters, swollen lymph nodes, and nausea. 

You are at more risk of cellulitis if you have a compromised immune system (e.g. due to cancer or an autoimmune disease), if you are overweight, have diabetes or lymphatic system issues. 

Cellulitis is easily treated with oral antibiotics. If the infection gets deeper into the body it can cause more serious issues which may require a visit to the hospital for intravenous antibiotics or to drain an abscess

Emotional impact of skeeter syndrome

The pain, swelling, and interruption to daily life can take a toll on sufferers’ mental health, especially if it becomes a common occurrence. The persistent discomfort can make people feel frustrated, irritable, and anxious about getting bitten again. Sufferers may actively avoid situations where they may get bitten, for example, social events during the summer. 

In particular, for children, Skeeter syndrome can cause emotional distress. The visible redness and swelling may affect self-esteem and can create anxiety about getting bitten in the future, which can make them unwilling to engage in outdoor activities. 


Skeeter syndrome is a rare, exaggerated allergic reaction to mosquito bites characterised by itching, swelling, redness, and tenderness. It is caused by an allergic reaction to proteins in the mosquitos’ saliva which enters the bloodstream when they bite us. Diagnosis involves a physical examination and allergy testing.

Skeeter syndrome is treated with antihistamines, painkillers, and hydrocortisone cream. In more serious cases, corticosteroids may be required to relieve the symptoms. Secondary infections can occur if the person scratches or picks the bite. It is important to know how to prevent and manage Skeeter syndrome, especially for those at risk, such as children and allergy-prone individuals. 

Some of the ways you can protect yourself are to wear protective clothing such as long sleeves and trousers, use mosquito repellant, and avoid areas where there are high concentrations of mosquitoes. 


  1. Vander Does A, Labib A, Yosipovitch G. Update on mosquito bite reaction: Itch and hypersensitivity, pathophysiology, prevention, and treatment. Front Immunol [Internet]. 2022 Sep 21 [cited 2024 Apr 10];13:1024559. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9532860/
  2. Ellwanger JH, Cardoso J da C, Chies JAB. Variability in human attractiveness to mosquitoes. Current Research in Parasitology & Vector-Borne Diseases [Internet]. 2021 Jan 1 [cited 2024 Apr 10];1:100058. Available from: https://www.sciencedirect.com/science/article/pii/S2667114X21000522
  3. Prasadini M, Dayananda D, Fernando S, Harischandra I, Silva ND. Blood feeding preference of female aedes aegypti mosquitoes for human blood group types and its impact on their fecundity: implications for vector control. Am J Entomol [Internet]. 2019 Jun [cited 2024 Apr 10];3(2):43–8. Available from: https://www.sciencepg.com/article/10.11648/j.aje.20190302.13
  4. De Obaldia ME, Morita T, Dedmon LC, Boehmler DJ, Jiang CS, Zeledon EV, et al. Differential mosquito attraction to humans is associated with skin-derived carboxylic acid levels. Cell. 2022 Oct 27;185(22):4099-4116.e13.
  5. Fernández-Grandon GM, Gezan SA, Armour JAL, Pickett JA, Logan JG. Heritability of attractiveness to mosquitoes. PLOS ONE [Internet]. 2015 Apr 22 [cited 2024 Apr 10];10(4):e0122716. Available from: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0122716
  6. Yamada M, Ishikawa Y, Imadome KI. Hypersensitivity to mosquito bites: A versatile Epstein–Barr virus disease with allergy, inflammation, and malignancy. Allergology International [Internet]. 2021 Oct 1 [cited 2024 Apr 10];70(4):430–8. Available from: https://www.sciencedirect.com/science/article/pii/S1323893021000782
  7. Manuyakorn W, Itsaradisaikul S, Benjaponpitak S, Kamchaisatian W, Sasisakulporn C, Jotikasthira W, et al. Mosquito allergy in children: Clinical features and limitation of commercially-available diagnostic tests. Asian Pac J Allergy Immunol. 2017 Dec;35(4):186–90.
  8. Hodgens A, Sharman T. Corticosteroids. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 [cited 2024 Apr 10]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK554612/
  9. McBride CS. Genes and odors underlying the recent evolution of mosquito preference for humans. Curr Biol. 2016 Jan 11;26(1):R41-46.
  10. Naveed M, Ali U, Aziz T, Naveed R, Mahmood S, Khan MM, et al. An aedes–anopheles vaccine candidate supplemented with bcg epitopes against the aedes and anopheles genera to overcome hypersensitivity to mosquito bites. Acta Parasit [Internet]. 2024 Mar 1 [cited 2024 Apr 10];69(1):483–504. Available from: https://doi.org/10.1007/s11686-023-00771-1

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This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Albertina Metson

Bachelor of Science, Neuroscience, University of Bristol, UK

I am a neuroscience graduate with an interest for all things science and health. I have a wealth of experience in both written and verbal communication, gained from my degree, several years of working in retail, and working as an academic mentor for younger students at my university. After writing for a range of audiences during my university career, I realised my love for medical writing.

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