Nearly everyone is sensitive to mosquito bites. But for those with severe allergies, symptoms can be more than just annoying: they can be downright serious. Most bites occur at either dusk or dawn, when mosquitoes are most active. While male mosquitoes are harmless — feeding only on nectar and water — the females of the species are out for blood.
A female mosquito locks onto her victim using a combination of scent, exhaled carbon dioxide, and chemicals in the person's sweat. When she finds a suitable meal, she lands on an area of exposed skin and inserts her proboscis to draw the victim's blood. The common symptoms — a telltale red bump and itching — aren’t caused by the bite itself, but by a reaction of the body's immune system to proteins in the mosquito's saliva.
Learn more about mosquito bite allergies, and whether an encounter with mosquitoes might be potentially harmful.
Researchers are unclear as to the reasons, but mosquitoes tend to prefer certain victims over others, including men, people who are overweight or obese, and those with type O blood. Also, because mosquitoes are attracted to heat, wearing dark colors (which absorb heat) may make a person more likely to be bitten. People living in humid, tropical climates are also at a greater risk.
The more times a person has been bitten by mosquitoes, the more likely they’ll become desensitized over time. That means adults typically have less serious reactions to mosquito bites than children do. Common symptoms of mosquito bites include soft bumps on the skin that may become pink, red, and itchy. Symptoms may occur up to 48 hours after the initial bite. According to the American Academy of Allergy, Asthma, & Immunology (AAAAI), contact with a mosquito must be six seconds or longer to produce a reaction.
Symptoms of a more severe allergic reaction may include:
- large area of itching
- bruises near the site of the bite
- lymphangitis (inflammation of the lymph system)
- hives (at or around the bite)
- anaphylaxis (a rare, life-threatening condition that results in swelling in the throat and wheezing and requires immediate medical attention)
Allergic reactions aren't the only concern regarding mosquito bites. Mosquitoes can also transmit serious diseases, such as:
- dengue fever
- encephalitis (brain infection)
- yellow fever
- West Nile Virus (found in North America)
- meningitis (brain and spinal cord inflammation)
Signs that it may be something other than an allergic reaction include:
- severe headache
- body aches
- nausea or vomiting
- light sensitivity
- neurological changes (such as muscle weakness on one side of the body)
Contact your doctor immediately if you experience any of these symptoms.
As with other allergies, prevention is the best approach. Mosquitoes require standing or stagnant water to breed. Avoid standing water especially at dusk and dawn when mosquitoes are most active, if possible.
Other ways to prevent mosquito bites include:
- wearing protective, light-colored clothing such as long-sleeved shirts, long pants, socks, and a wide-brimmed hat
- eliminating standing water around the home (unclog rain gutters, empty children's pools, clean birdbaths, and empty unused containers such as flower pots)
- repairing holes in window or door screens
- using citronella-scented candles in outdoor areas or campsites
It’s also important to apply insect repellents containing DEET. The AAAAI recommends using products that have between 6 and 25 percent DEET. These provide up to six hours of protection. Follow directions carefully, and reapply after swimming or sweating. Since repellants can also cause adverse skin reactions, test the product on a small area of your arm and wait 24 hours to make sure it’s safe to use on your entire body.
Even the best preventative measures probably won't protect you from all bites. In the case of a normal reaction, a hydrocortisone cream or calamine lotion will provide relief from itching. A cold pack, ice cubes or a cool bath without soap may help relieve symptoms as well. For more serious allergic reactions, the following treatments may be used:
- oral antihistamines (such as Benadryl or Claritin)
- topical anti-itch lotion or benzocaine
- a cool bath without soap
- an epinephrine autoinjector (EpiPen) to carry on-hand in case of anaphylaxis
Mosquito bite allergies are rare, but the reactions can be serious enough to warrant immediate medical treatment. If you have this type of allergy, you may consider ongoing treatment from an allergy specialist — especially if you live in mosquito-prone areas. Mosquito bite allergies don’t cause any long-term illnesses or lifestyle intrusions when they’re properly managed. Just be aware of these pests and have the right tools on hand in case you get bitten.