DEAR DR. ROACH: My wife does a lot of container gardening. I am continually being bitten by chiggers. I have been using an over-the-counter anti-itch cream that helps soothe the bites, but it doesn’t eliminate the symptoms. Is there anything to prevent the infestation or end the long-term itching?

— J.F.K.

ANSWER: Never having lived in the South, I don’t know a lot about chiggers — scientifically, Trombiculidae larvae, the little “red bugs” that are arachnid mites, not insects. They don’t get a lot of medical attention in North America, as the species we have here do not transmit disease.

However, I have read that the bites are extremely itchy. If over-the-counter anti-itch creams like calamine or menthol don’t help, the next step in treatment is with topical steroids, which range in strength. Potency can be enhanced by plastic wrap over the medicated area.

Prevention is probably your best bet. Keeping away from chiggers is best; if that’s not possible, wear protective clothing and wash yourself vigorously with soap and water after possible exposure. A chemical repellant such as DEET may be of value as well.

You might also consult with someone with gardening skills and experience about these pests, as I read there are some mechanical means of controlling the population of chiggers. That’s outside of my area of expertise.

DEAR DR. ROACH: Quite by accident, I have found a home remedy for poison ivy and poison oak. As an avid gardener, I get poison ivy once or twice a year. I always wash my hands, arms and any affected area with liquid soap. However, this time I was out of soap and used a liquid detergent with a degreaser. I put a small amount on my arm, rubbed it down my arm and added water to wash it off. I have tried different detergent degreasers over the past several months, and any one will work. It makes sense, because poison ivy and oak have urushiol oil, and of course a degreaser would dissolve it and wash it away. I hope you can pass this on to your readers!

— F.C.

ANSWER: I appreciate your writing, and I agree with your take on the issue. Poison oak, ivy and sumac all have the same irritating oil, urushiol, which is one of the few substances that can cause a severe hypersensitivity reaction the first time a person is exposed to it. Repeated exposures are often worse.

The most important advice on these poisonous plants is not to get exposed in the first place. That means removing it if it’s in your yard, if possible, and knowing how to recognize and avoid it. Protective clothing is essential if you must be near it.

If you are exposed inadvertently and recognize it, then removing the oil is urgent: Within 10 minutes is best, but washing off will help even if it’s two hours after exposure. Washing after the rash shows up isn’t helpful. Warm water with soap or detergent is recommended, but don’t over-vigorously scrub, because damaging the skin can make the rash worse. The oil can stay under the fingernails and on clothing.

Clean under the nails carefully and wash clothing in hot water.

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Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.