How to protect yourself from mosquito bites

Mosquito bites are irritating at best and vectors for disease at worst.

Depending on what country you are in, they can transmit malaria, dengue fever, West Nile, yellow fever and Zika, among other maladies.

As global temperatures rise, mosquito season is getting longer in many parts of the United States. And, some people are magnets for mosquitoes. (It may be because of how you smell.)

The good news is that there are a range of insect repellents and essential oils that you can spread or spray on your skin — and some are more effective than others. The Washington Post asked mosquito experts about the best ways to prevent bites — and whether things like citronella candles help at all. Here’s what they said.

What is the most effective mosquito repellent?

Mosquito experts say the “gold standard” for preventing bug bites is DEET, a synthetic repellent developed 80 years ago to help the U.S. Army keep mosquitoes away. Despite reassurance from experts about its safety, some people aren’t comfortable spraying DEET on themselves, on their children or while pregnant. (DEET can be found in some of the most common bug sprays on the market. Check the label.)

In the 1980s and ’90s, there were reports of adverse health effects in children and adults after they ingested or repeatedly used DEET. But subsequent studies have found that DEET presents little to no risk when used as instructed.

“If you use this stuff as the directions say, your risk is minuscule of anything negative happening to you, and we’ve been using this thing for a long time,” said Jeffrey R. Bloomquist, a retired professor formerly at the Emerging Pathogens Institute at the University of Florida.

The Centers for Disease Control and Prevention considers DEET to be safe and effective even for those who are pregnant or breastfeeding. The American Academy of Pediatrics recommends that parents use DEET “sparingly” on children younger than 2 years old.

What if I’m not comfortable using DEET?

The EPA has a list of active ingredients that have been found to be safe and effective as skin-applied insect repellents. Look for products that have an EPA registration number on the label.

Picaridin, another synthetic repellent registered by the Environmental Protection Agency, has been found to be as effective — or even more effective — at repelling mosquitoes as the same concentration of DEET.

And, experts say picaridin doesn’t have the oily feeling or odor some brands of DEET can have.

Those who aren’t comfortable applying DEET directly to their skin can spray it on their clothing instead, particularly the cuffs of long-sleeved shirts and pants, said Chris Adigun, a board-certified dermatologist in Chapel Hill, North Carolina. Just note that the repellent should not be applied under clothing, and it can damage some plastics and synthetic materials.

For those who want a naturally derived bug repellent, the EPA has registered products with oil of lemon eucalyptus (OLE). But, the American Academy of Pediatrics does not recommend oil of lemon eucalyptus for children younger than 3.

How long do repellents last?

EPA-registered repellents will state how long a product will last on the label, said Scott Carroll, president of Carroll-Loye Biological Research, an insect-repellent testing laboratory. And, he said those are the result of “carefully conducted” science.

“The registered ones have data behind them that are backing them up,” Carroll said.

Do essential oils repel mosquitoes?

There is some evidence that certain essential oils can protect against mosquitoes. But there isn’t enough research regarding how long these last and how the products stack up against EPA-registered repellents.

In one study, researchers tested 20 essential oils against both ticks and mosquitoes and found that clove oil was the most effective against mosquito bites, with a complete protection time of nearly two hours, while cinnamon oil protected for about 80 minutes.

“There is repellency in certain essential oils,” said Whitney Qualls, the assistant director of the Anastasia Mosquito Control District in St. Augustine, Florida. But the total protection time an essential oil provides can vary from product to product and even within the same product when companies source from different suppliers, Qualls said.

“If you are in an area where you have mosquito-borne disease transmission and that is your concern, you should wear a repellent that has an EPA-registered active ingredient,” Qualls said.

For the essential oil experiments, the researchers mixed one part essential oil with nine parts lotion and applied the repellent directly to the skin. But many store-bought products typically use about a 5% (or less) concentration of essential oils, said Immo Hansen, senior author of the study and a professor of biology at New Mexico State University who studies disease vectors.

These small concentrations may not be as effective.

Check with your physician or your children’s pediatrician before using products containing essential oils. And don’t try to make your own repellent.

Certain oils may not be safe for frequent and long-term use on skin, Carroll said.

“It’s important that essential oils not be regarded strictly as benign,” he said. “They won’t be for all individuals.”

What about ultrasonic or other devices?

Wearable ultrasonic devices are rarely successful at repelling mosquitoes, according to Daniel Markowski, technical adviser for the American Mosquito Control Association.

Bug zappers are exceptionally good at electrocuting bugs — but not mosquitoes.

Markowski said the “more effective” devices rely on a repellent. Anyone can buy what’s known as a spatial repellent, which releases a vapor containing a compound like metofluthrin, for example. But, Markowski said “unless that vaporized repellent encompasses your entire body, they’re just going to bite you on the leg versus the hand.”

A simple fan could ward off mosquitoes, Makowski said. But, the fan has to be on a pretty high setting to push away mosquitoes that are flying against the wind. And, “if you’ve got a fan that that’s strong, you’re getting blown in the face,” he said.

And while some studies suggest that citronella candles may help a little, they are not as effective as other methods for warding off mosquitoes. One study found a citronella candle had no effect on the insects.

“If you’re one of those individuals mosquitoes absolutely love — they’re always going to find you out in the field — then you probably need a little bit stronger repellent,” Markowski said.

What else can I do to prevent mosquito bites?

Make sure all window screens in your home are in good shape and have a proper seal. Conduct perimeter checks outside your home to make sure there’s no standing water, debris or empty containers that could serve as homes for mosquitoes.

Try to limit outdoor activities during dawn and dusk — when mosquitoes are most active. When you’re outside, cover up. Wear long-sleeved shirts and long pants to protect against mosquitoes, ticks and other insects. Mosquito nets are also a good option to protect babies — just drape them over the stroller, for instance.

When should I be concerned about a mosquito bite?

When a mosquito bites, people often have a “localized reaction,” with redness and potential swelling, said Marc Siegel, a professor of medicine at George Washington University’s School of Medicine and Health Sciences.

The mark from a mosquito bite is the skin’s reaction to the cocktail of proteins and enzymes in the insect’s saliva — including an anesthetic to keep the host from feeling any pain and an anticoagulant to keep the blood flowing. If the bug bite doesn’t go away or gets worse after two to three days, contact your doctor, Siegel said.

West Nile virus is the “most widespread” mosquito-borne virus in the United States, Siegel said. Most people infected who are infected “aren’t even aware” they have it and experience no symptoms. About 1 in 5 people with West Nile virus develop a fever, headache, body aches or a rash, among other symptoms, according to the CDC. But Siegel said we’re seeing more cases of other “equally concerning” infections, such as Dengue fever, among U.S. travelers who became infected abroad.

People who experience flu-like symptoms after a mosquito bite should contact their physician.