Symptoms

Common signs and symptoms
Typical signs and symptoms of mosquito bites include:

• Soft, initially pale bumps on your skin that can become pink or red
• Itching

The bump that results from a bite can appear immediately or may take up to two days to appear. If you're highly sensitive to mosquito bites, you may have a much larger area of itching.

Severe allergic reaction
Rarely, a serious reaction to mosquito bites might occur, which results in swelling in the throat, significant hives and wheezing. This life-threatening condition (anaphylaxis) requires immediate medical attention.

Mosquito-borne disease
Mosquitoes can transmit serious diseases such as West Nile virus, malaria, yellow fever and dengue fever. Signs and symptoms of a more serious infection may include:

• Fever
• Severe headache
• Neurological changes, such as one-sided muscle weakness
• Body aches
• Nausea
• Vomiting
• Swollen glands
• Rash
• Lethargy
• Confusion
• Sensitivity to light

When to see a doctor
If a mosquito bite seems to be associated with more serious signs and symptoms — such as fever, severe headache, body aches, nausea and vomiting — contact your doctor.

Causes

Mosquito bites are caused by the bite of a female mosquito. The female mosquito feeds off your blood by piercing your skin with her mouth (proboscis). While sucking your blood, she also deposits some of her saliva into your skin. This saliva contains proteins that remain in your skin. Your immune system may then react to those proteins, resulting in the characteristic itching and bump.

Risk factors

Mosquitoes select their victims by evaluating scent, exhaled carbon dioxide and the chemicals in a person's sweat. A few factors may put you at greater risk of getting bitten. Although it's not clear why, mosquitoes are more likely to bite:

• Men
• People with type O blood
• Overweight people

In addition, mosquitoes are attracted to heat. So, wearing dark colors, which absorb heat, may attract mosquitoes.

Age can affect symptom severity
Adults may become less sensitized to mosquito bites if bitten many times throughout life. This means adults are less likely to have strong reactions to mosquito bites. Children who haven't been bitten as much are at greater risk of experiencing symptoms from a mosquito bite.

Complications

• Infected bites. If you scratch mosquito bites, any resulting sores could become infected.
• Mosquito-borne diseases. Mosquitoes can act as reservoirs of diseases such as West Nile virus, malaria, yellow fever and dengue fever. The mosquito obtains a virus by biting an infected person or animal. Then, when biting you, the mosquito can transfer that virus to you through its saliva. West Nile is found in the United States. Other diseases such as malaria and dengue fever are far more common in tropical areas of the world. However, malaria and dengue fever are rare in the United States.
• Severe allergic reaction (anaphylaxis). Although rare, a serious reaction to mosquito bites might occur, which can result in swelling in your throat, significant hives and wheezing. This requires immediate medical attention.

Complications

You won't need to see your doctor for a mosquito bite, but if you notice that the redness, swelling or pain is getting worse over time, instead of better, or if you develop a fever or other signs and symptoms of illness you feel might be associated with a mosquito bite, you'll need to visit your primary care physician.

Here's some information to help you get ready for your appointment.

What you can do

• Make a list of all medications, vitamins and supplements that you're taking.
• Write down any questions you may have.

If you're having symptoms you think might be related to a mosquito bite, some basic questions you might have include:

• What can I do to stop the itch?
• Is the area around my mosquito bite infected?
• Does the medication you're prescribing have any side effects?
• How will I know if I need additional care?

What you can do in the meantime
If you know you've been bitten by a mosquito, wash the area with soap and water as soon as possible. This may help lessen the reaction.

An ice pack may help reduce the swelling, and if the itching is a problem, an over-the-counter antihistamine may help. Examples include diphenhydramine (Benadryl), chlorpheniramine maleate (Chlor-Trimeton), loratadine (Claritin) or cetirizine (Zyrtec).

Tests and diagnosis

If you have an infection at the site of your bite, your doctor can diagnose this by looking at it. If you've contracted an illness from a mosquito bite, your signs and symptoms are usually enough for your doctor to diagnose the illness, but a blood sample may sometimes be taken to confirm the diagnosis. For some complications, including meningitis or neurological changes that occur after exposure to mosquitoes, additional tests, such as a spinal fluid examination, may be needed.

Lifestyle and home remedies

Topical treatments
If you scratch mosquito bites, you could break your skin, which may lead to a bacterial infection in your skin (cellulitis). Instead of scratching, try applying a hydrocortisone cream, calamine lotion or a paste. To make a paste, take about 1 teaspoon (about 5 milliliters) of water and mix with an equal volume of dry meat tenderizer. Apply several times a day until your symptoms subside. A cold pack or baggie filled with crushed ice may help, too.

Oral antihistamines
For stronger reactions, taking an antihistamine containing diphenhydramine (Benadryl, Tylenol Severe Allergy), chlorpheniramine maleate (Chlor-Trimeton, Actifed), loratadine (Claritin) or cetirizine (Zyrtec) may ease your body's response.

Alternative medicine

There's some evidence that taking 75 to 150 milligrams of vitamin B-1 (thiamin) each day during the summer may slightly change your scent and offer some protection from insect bites. However, this hasn't been definitively proved.

Prevention

To prevent mosquito bites, take steps to reduce the mosquito population around your home. Using insect repellents and protective clothing also can help.

Reducing mosquitoes around your home
Mosquitoes need stagnant or standing water to breed. Eliminate standing water, especially after rains, and you can reduce the mosquito population around your home and yard.

To eliminate standing water:

• Unclog roof gutters.
• If possible, empty children's wading pools at least once a week, and preferably more often.
• Change water in birdbaths at least weekly. You can also purchase devices to place in birdbaths that keep the water circulating so that mosquitoes won't lay eggs there.
• Get rid of old tires in your yard, as they collect standing water.
• If you keep unused containers, such as flower pots, in your yard, empty them regularly or store them upside down so that they can't collect water.
• If you have a fire pit, drain any collected water regularly.

Other methods of controlling mosquitoes may be popular, but their effectiveness is unproved. These methods include:

• Electronic insect control systems, better known as bug zappers
• Citronella-scented candles
• Attracting birds and mammals that feed on mosquitoes

Insect repellents
When used properly, repellents are safe for kids and adults alike. Keep in mind that repellents don't kill mosquitoes; they just make it harder for them to find you. That means even when a repellent is working, you may still see these annoying insects buzzing about.

Common insect repellents include:

• DEET. The pesticide DEET blocks a mosquito's ability to find people who've applied it.

  Apply repellent with up to a 35 percent concentration of DEET to your skin and clothing. Choose the concentration based on the hours of protection you need — generally, the higher the concentration of DEET, the longer you are protected. A 10 percent concentration protects you for about two hours. Keep in mind that chemical repellents can be toxic, and use only the amount needed for the time you'll be outdoors. Don't use DEET on the hands of young children or on infants younger than age 2 months.

• Picaridin. This repellent, also called KBR 3023, offers protection that's comparable to DEET at similar concentrations. It also blocks a mosquito's ability to find people who've applied it. Picaridin is nearly odorless, which may make it a good alternative if you're sensitive to the smells of insect repellents.
• Oil of lemon eucalyptus. This plant-based chemical may offer protection that's comparable to low concentrations of DEET. Don't use this product on children younger than 3 years.
• Others. Shorter acting repellents — such as citronella — may offer limited protection.

Check the labels of insect repellent products to see which chemicals or other ingredients they contain. And be sure to follow the product's application guidelines. When you come indoors, wash your skin and your children's skin with soap and water to remove any remaining repellent.

Protective clothing
What you wear can also help keep mosquitoes at bay. Keep these clothing tips in mind, particularly in areas that are heavily infested with mosquitoes:

• Wear long-sleeved shirts.
• Wear socks.
• Wear long pants and consider tucking your pants into your socks.
• Wear light-colored clothing, since mosquitoes are more attracted to darker colors.
• Apply permethrin-containing mosquito repellent to your clothing, shoes, and camping gear and bed netting. You can also buy clothing made with permethrin already in it.
• Wear a full-brimmed hat to protect your head and neck or a baseball cap with a fold-out flap to protect the back of your neck. And, when you're in an area with a significant mosquito population, consider wearing a mosquito net to cover your head and face.
• Cover an infant seat or stroller with mosquito netting for extra protection.

In addition to these steps, fix any holes you might have in your window or door screens.