By Steven Howard, M.D.

Summer is a time for baseball and barbeques. Unfortunately, it’s also the time for poison oak, mosquitoes and ticks.

Poison Oak
Poison oak is covered by an oily resin called urushiol, which can cause a rash. You can get poison oak from anything that comes into contact with the plant, including pets, garden tools or shoes. After exposure, the rash can take up to 21 days to appear.

The rash, and even the oozing blisters, are not contagious and will usually clear up in one to three weeks. Treatment includes calamine, antihistamines and cortisone creams. Don’t use anesthetics (Benzocaine) or Neosporin, which will make the symptoms worse.

If you suspect you or your child has been exposed to poison oak, you may think an immediate bath is a good idea, but it is not! The resin is oily and is not water soluble, so it floats to the surface. Rather than washing it off, you will likely cover you or your child with the resin instead.

Prevention is the best protection against poison oak. When clearing poison oak from your yard, always use vinyl gloves since the resin can penetrate cotton and latex gloves. You can also apply a product called Ivy Block every four hours to prevent the resin from penetrating your skin, but it’s important to wash it off as soon as possible. Be sure not to burn any parts of the poison oak plant, or you run the risk of inhaling the resin.

If you or your child is very sensitive to poison oak, it’s important to know that mango skins also contain urushiol and can cause the same reactions.

Mosquitoes and Ticks
Now let’s talk about the mosquito and the tick. While mosquito bites are mostly just annoying, 5 percent of global deaths result from diseases spread by these critters. One example is the West Nile virus, but the good news is that very few people contract or grow ill from this virus.

Tick bites can cause Lyme disease, which is also a rarity in our area. Lyme disease is carried by deer ticks, which are about the size of poppy seeds. For this reason, about two-thirds of people infected with Lyme disease have no idea they even suffered a tick bite.

Most insect repellants work for both mosquitoes and ticks. The most commonly used repellants are DEET and Picaridin, which can be applied to the skin and clothing. These repellants can be used by children down to 2 months of age, as well as by pregnant and breastfeeding women, but it’s important to avoid eye contact and inhalation. Permethrine works well when it’s applied to clothes and allowed to dry for two hours before wearing. Skin So Soft and Citronella also provide some benefit, but there’s no evidence that electronic repellants provide any benefit.

For tick prevention, you can wear light-colored clothing when hiking so you can easily see ticks on your clothes. Check yourself carefully when you get home, especially in warm, moist areas and on the scalp. It usually takes hours for a tick to attach and more than 24 hours for it to spread any infection.

What happens if you find a tick has latched on? Forget about matches and nail polish—they only annoy the tick. Grasp the tick’s head with a fine tweezers as close to the skin as possible, then pull it straight back—slowly and without squeezing. Clean the wound and don’t worry if some small parts of the tick remain—they will be expelled as the skin heals.

Dr. Howard is a family medicine physician at PAMF's Redwood City Center.