Nearly everyone is sensitive to mosquito bites but, for those with a severe allergy, 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.
Who Is at Increased Risk for Mosquito Bites?
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.
The more times a person has been bitten by mosquitoes, the more likely they’ll become sensitized 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. Symptoms of a more severe allergic reaction may include:
- large area of itching
- lymphangitis (inflammation of the lymph system)
- hives, which may appear at the site of both new and old bites
- anaphylaxis: although rare, anaphylactic shock is a 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 malaria, dengue fever, and yellow fever (all rare in Western countries). Mosquitoes may also transmit the West Nile virus (found in North America). 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)
A person exhibiting the above symptoms or other complications such as infection at the site of a bite after being bitten by a mosquito should contact their doctor immediately.
As with other allergies, prevention is the best medicine. Mosquitoes require standing or stagnant water to breed. If possible, avoid standing water especially at dusk and dawn when mosquitoes are most active. 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)
- applying insect repellents such as DEET (follow directions carefully) or use citronella-scented candles in outdoor areas or campsites
- repairing holes in window or door screens
There is limited evidence that taking vitamin B-1 (thiamin) during the summer also may provide some protection against mosquito bites as well. Thiamin is thought to work by slightly changing a person's scent. Studies are ongoing.
Mosquitoes haven't survived for millions of years by being anything less than determined. Even the best preventative measures probably won't avert all bites. In the case of a normal reaction, a hydrocortisone cream or calamine lotion will provide relief from itching. A cold pack or ice cubes may help to relieve symptoms as well. For more serious allergic reactions, the following treatments may be used:
- Take oral antihistamines (such as Benadryl or Claritin).
- Use topical anti-itch lotion or athlete's foot spray.
- For hives, take a cool bath without soap or place ice cubes on itchy areas for 10 minutes.
- A person in danger of anaphylaxis should carry an epinephrine autoinjector (EpiPen) in case of an emergency.