All you need to know about insect repellents before traveling: types, usage, side effects and most common brands

Introduction

Annually, millions of United State tourists visit countries where they are at increased risk of infectious disease acquisition. Some of those infections are spread through mosquitos (mosquito-borne) and ticks (tick-borne infection). In order to prevent the transmission of these infections and their complications (sometimes life-deadly), it is important to avoid insect bites. For that purpose, healthcare professionals recommend using insect repellents along with other preventive methods (wearing long-sleeved clothes, sleeping under the mosquito nets) while being in a risky region.

Which infections may be prevented with insect repellents?

If used correctly, the insect repellent will protect a person from infections transmitted through mosquitos and ticks. The list of these infections is stated below.

An insect that transmits the infection	Disease
Mosquito	Zika
	Malaria
	Dengue fever
	Yellow fever
	Japanese Encephalitis
	West Nile Virus
	Chikungunya virus
Tick	Encephalitis
	Lyme disease
	Rocky Mountain Spotted Fever
	Ehrlichiosis

How to choose the repellent?

Several things that need to be considered when choosing a repellent.

It is extremely important to choose a product that is registered by the United States Environmental Protection Agency (EPA). Otherwise, a person will get a product of questionable safety and effectiveness.
From which insect a person should be protected (mosquito, tick, or both of them)
How much protection time is needed
Who will use the repellent? People aged 40 and older, and/or those with suppressed immunity, need a repellent with a higher dose of DEET (up to 50%). Whereas, children should never use a repellent with higher than 30% DEET.

DEET vs non DEET products (natural products)

Different repellents have different active ingredients in them. A table below summarizes the benefits and disadvantages of the most common ones:

Ingredient	Advantages	Disadvantages
DEET	In use for 7 decades Protects from different types of insects Meets safety standards It does not cause cancer Is safe for pregnant women It is safe for children aged 2 months old and older	It may damage clothes if those are synthetic It is a synthetic repellent When used excessively it may cause dermatitis and/or allergy In very rare case sit may cause neurotoxicity (have an unpleasant effect on the nervous system) It may be a bit oily or sticky
Picaridin	It does not cause adverse effects It has a natural compound It does not damage the clothes It is odorless It is colorless	Less effective than DEET (especially the protection against ticks) No evidence of being safe for pregnant women
IR 3535		It has the lowest effectiveness It is a synthetic repellent
Oil of Lemon Eucalyptus (PMD)	It has a natural compound	It has about 2 times lower effectiveness compared to DEET It may cause skin irritation There is no evidence of it being safe for children
BioUD	It has a natural compound It has the lowest toxicity among other ingredients	Higher doses are needed to rich the sufficient protection
Metofluthrin (Off! Clip-on Mosquito)	Has high effectiveness	May cause local irritation and burning

What is the sufficient amount of DEET in repelling?

Nowadays, the concentration of DEEP in repellents varies from 5% to 100%. The sufficient amount of DEET in repelling depends on the needed protection time. The approximate protection time of DEET containing repellents ranges from 2-10 hours for ticks and 2-12 hours for mosquitos. A product that contains 10% of DEET will protect for 2 hours. Whereas, the one that contains 24%, will give a 5 hours protection.⁴The protection time increases with the amount of DEET in repellent. However, repellents having more than 50% of DEET, do not tend to follow this rule anymore (the protection time stops to increase).

The needed information on the active ingredient, protection time and DEET percentage of the repellent, may be found on the following website: https://www.epa.gov/insect-repellents/find-repellent-right-you (it is just needed to fill the required fields of the table on the bottom of the webpage).

Where to apply the repellent?

Some recommendations should be followed when applying an insect repellent:⁷

Read the directions mentioned on the package of the repellent
The repellent should be applied to potentially exposed areas of the body and clothes (remember that DEET products damage synthetic clothes).
It should never be applied under clothes.
The application of the product on sensitive areas such as eyes and mouth should be avoided.
The repellent should be applied in minimal amounts around the ears.
The product should never be applied to wounds, cuts and/or irritated body parts.
The product should not be sprayed near food
It is not recommended to apply the product directly on the face. It is better to spray it on the hands and then apply it on the face.
It should never be sprayed in enclosed areas
Sunscreen and repellent should not be mixed. First, the sunscreen should be applied then the repellent.
The hands should be washed after applying the product
Once a person comes home he/she should take a shower and wash his/her clothes

How often to apply the repellent?

Each repellent has its protection time. That is why it is important to follow the directions mentioned don the label. Certain factors may require a more frequent application of the product. Those are:

High humidity
Exposure to water
Perspiration

Potential side effects of repellents

As it has been mentioned before, repellent-related side effects may include:

Local irritation
Local burning
Neurotoxicity (very rare)
Itching

What to do if a side effect occurs?

Side effects of repellents are rare, but if those occur it is important to follow the recommendations listed below:

It is important to stop using the product
The affected skin should be washed immediately
The person should contact the local Poison Control Center (Phone: 1-800-222-1222)
In the case of visiting a health facility, the patient should show the repellent to the health provider

Common brands of repellent in the USA?

The most widely used insect repellent brand in the USA (2013-2020 estimates) are:

Off! (contains DEET)
Cutter (DEET-free)
Repel (DEET-free, active ingredient is the oil of lemon eucalyptus)
Coleman (IR 3535)

How much should I spend on repellent?

The prices of insect repellents vary from brand to brand. The famous Off!® repellents cost around 5-10 US dollars. Repel® and Cutter® cost around 6 US dollars. So, on average, there is no big difference between the prices of the famous repellent brands.

Conclusion

Today, different types of repellents, of different origins exist. The most effective ones are considered to be those having DEET as an active ingredient. However, the ones that have other active ingredients also have advantages that should be taken into consideration. A person should find a product that corresponds to his/her needs. Also, a traveler should never forget to read and follow the product-specific recommendations.

References

Center for Global Health Division of Parasitic Diseases and Malaria Insect Repellents Help Prevent Malaria and Other Diseases Spread by Mosquitoes Why Do I Need to Use an Insect Repellent When I Travel to an Area with Malaria? CDC.
Risk of Disease from Mosquito and Tick Bites | Repellents: Protection against Mosquitoes, Ticks and Other Arthropods | US EPA.
Find the Repellent that is Right for You | Repellents: Protection against Mosquitoes, Ticks and Other Arthropods | US EPA.
Prevention of arthropod and insect bites: Repellents and other measures - UpToDate.
Insect Repellent Q & A | Tick-Borne Disease | Health & Senior Services. Accessed January 18, 2020.
DEET | Repellents: Protection against Mosquitoes, Ticks and Other Arthropods | US EPA.
Using Insect Repellents Safely and Effectively | Repellents: Protection against Mosquitoes, Ticks and Other Arthropods | US EPA.
NC DPH: Safe Use of Insect Repellents.