Q: I am confused about how to prevent swimmer’s ear. A lot of websites suggest putting alcohol in the ears after swimming. But is it 50% or 90%? What about vinegar? Is the correct solution half alcohol and half vinegar? Please help me figure this out.

A: You can purchase over-the-counter ear drops to prevent swimmer’s ear. Most contain 95% anhydrous isopropyl alcohol and 5% anhydrous glycerin (“anhydrous” means it contains no water).

Here is what one reader wrote: “I mix a solution of (one part) isopropyl alcohol and (one part) vinegar. I put it in the ear canal with a dropper after swimming, let it stand for a little while and then empty the ear canal.

“The alcohol dries the water, and the vinegar leaves an acidic base for the ear canal, so fungus won’t grow. I have been using this solution for years, but I am careful not to use this too often so that I don’t get dry skin in my ears.”

Q: Last summer, I had a painful rash under my breasts. My dermatologist recommended Zeasorb AF. She emphatically said to make sure it was the AF and not just plain Zeasorb. I have had no issues with the rash since I have been using Zeasorb AF.

A: During hot weather, skin folds often collect sweat and make a hospitable growing environment for fungus. This, in turn, can cause an uncomfortable rash that may be hard to treat. The medical term for this condition is inframammary intertrigo.

Zeasorb AF contains the antifungal agent miconazole and no starch. That explains your dermatologist’s recommendation. Plain Zeasorb (super absorbent powder) is listed as containing cornstarch as the first ingredient.

Others have also had good results using antifungal products to treat under-breast rash. Here is what one reader wrote: “A friend told me to use Monistat cream and after it healed to use Desenex powder to keep the area dry. I did, and in three days the rash was gone. I had suffered with it for many years, but now I make sure I have Monistat and Desenex powder in my first aid kit.”

Monistat and Monistat 3-Day both contain miconazole, and so does Desenex. Another reader recommends a nondrug treatment: “Prevention is better than sticky creams. A company called More of Me to Love sells underboob soft bamboo cotton inserts for your bra to go under the breasts. They absorb sweat wonderfully and keep you dry all day. No more rash.”

Q: When I was in my early 40s, I was diagnosed with serious osteoporosis. I did the prescribed exercises and took Fosamax for nearly 20 years.

When I was diagnosed with Barrett’s esophagus, I had to stop the alendronate (Fosamax). It can harm the esophagus, so I took PPIs to protect myself from cancer of the esophagus.

Since then, I have not used any medication for my bones. My primary care physician wants me to use Prolia. I am aware of the possible side effects. If I couldn’t tolerate it, would there be any risks to stopping?

A: You are right to be cautious. Stopping denosumab (Prolia), even just missing a dose, can lead to fractures of the vertebrae. If you had to stop the Prolia, you’d have to go on a bisphosphonate, like alendronate, right away to prevent the fracture risk. Ask your primary care doctor to review all the other possible treatments for osteoporosis so you have an idea of your options.

In their column, Joe and Teresa Graedon answer letters from readers. Send questions to them via www.peoplespharmacy.com.