DEET or picaridin repellent, used according to the label, is a reasonable choice for children when dengue is a concern. "Natural" ingredients are not automatically safer, and the options extend beyond DEET and citronella.

DEET has been extensively reviewed. The US Environmental Protection Agency concludes that using it as directed on the label does not present a health concern, including for children. It can occasionally cause skin irritation. [EPA’s DEET review](https://www.epa.gov/insect-repellents/deet)

When choosing a repellent, check its active ingredient, concentration, age restrictions and protection time. Claims such as "natural" or "for kids" tell you less about whether it suits your child.

- Picaridin, also called icaridin, is an effective alternative to DEET. A 20% product is a practical choice for several hours of protection if the label permits use at your child’s age.
- DEET products containing 10% to 30% are commonly recommended for children older than two months. Higher concentrations mainly extend protection: roughly two hours for 10% and five hours for 30%. Age restrictions differ between countries, so follow local guidance and the product label.
- Oil of lemon eucalyptus/PMD is effective in formulated repellents, but avoid it for children under three. It is different from plain eucalyptus essential oil.
- Citronella and other essential-oil products often provide brief protection, or their effectiveness is less well established. I would not rely on them alone where dengue is a risk.

These recommendations come from the [American Academy of Pediatrics](https://www.healthychildren.org/english/safety-prevention/at-play/pages/insect-repellents.aspx) and [CDC guidance](https://www.cdc.gov/mosquitoes/prevention/index.html). Choose a product approved by your country’s regulator. In the US, look for EPA registration.

The evidence reviewed by the National Pesticide Information Center does not establish that inhaling citronella causes lung cancer in people. Research on the whole oil is limited, and animal findings involving one minor constituent do not establish that ordinary citronella use causes human lung cancer. Citronella can cause skin irritation or allergies. [Citronella fact sheet](https://npic.orst.edu/factsheets/citronellagen.html)

An adult should apply repellent to a child’s exposed skin, keeping it away from their hands, eyes, mouth, cuts and irritated areas. To apply it to their face, put it on your hands first. Avoid spraying in enclosed rooms or applying it underneath clothing. Reapply only as the label directs, and wash it off when protection is no longer needed. For babies under two months, start with clothing and mosquito netting. [EPA application advice](https://www.epa.gov/insect-repellents/deet), [CDC infant guidance](https://wwwnc.cdc.gov/travel/destinations/traveler/children/indonesia)

Combine repellent with measures to keep mosquitoes out and reduce places where they breed:

- Install or repair window and door screens, keep doors closed, and use air conditioning if available.
- Wear long sleeves and trousers, and put mosquito netting over strollers or carriers.
- Once a week, empty and scrub items that hold water, including flowerpot saucers, vases, buckets and toys.
- If mosquitoes persist, contact local mosquito control or a pest-control professional.

Mosquitoes can still enter from outside even if your home has no breeding sites. [CDC home-control advice](https://www.cdc.gov/mosquitoes/mosquito-control/mosquito-control-at-home.html/)

Protect against bites during the day too. Dengue-carrying mosquitoes commonly bite during daylight, so a nighttime bed net alone does not provide enough protection. [CDC dengue mosquito facts](https://stacks.cdc.gov/view/cdc/31032/cdc_31032_DS1.pdf)

How old are your children, and which country are you in? Their ages and your location would help narrow down the appropriate label restrictions.