DEAR DR. ROACH: I’m a 74-year-old woman who’s quite healthy (I am active and don’t take any medications), but I have a history of irritable bowel syndrome (IBS-C). Recently, I experienced bad-smelling gas, leg cramps, and finger and toe spasms. I quit eating milk products, and my symptoms almost immediately disappeared. My question is: Do food intolerances increase with age? Also, can leg cramps and digit spasms be attributed to a food intolerance?

• H.W.

ANSWER: The most likely diagnosis is lactose intolerance. This is caused by a deficiency in the enzyme lactase, which is used to split milk sugar into its constituent simple sugars. This condition is rare in childhood and does increase with age.

I’ve seen people with lactose deficiencies who complain about abdominal cramps, but digit spasms and leg cramps aren’t usually described with this deficiency. I’ve seen these symptoms in people with severe celiac disease due to low calcium levels. Since your symptoms disappeared when stopping milk products, it seems clear that these are, indeed, symptoms of a lactase deficiency, but they’re unusual enough that they aren’t well-described.

DEAR DR. ROACH: My husband has had neck pain for over two years. He has been treated with ablation of the neck nerves but hasn’t experienced any significant lessening of the pain. He’s been on oxycodone for at least a year. Nothing seems to be working on lessening his pain on a continuous basis. What’s your opinion on fentanyl patches? He’s 88 and very weak, but he doesn’t have any major physical problems.

• D.S.

ANSWER: Fentanyl is a very potent synthetic opiate, and the patch allows continuous absorption through the skin. It’s useful for people who need strong opiates, such as those with cancer. Unfortunately, opiates aren’t always a good choice for muscular or skeletal pain, which is likely the cause of your husband’s neck pain. If oxycodone isn’t working well, fentanyl probably won’t either. The body can quickly get used to high doses of any opiate.

Without knowing a lot more about his neck pain, I can’t make any definitive recommendations. Pain management experts will often try other types of injections, along with different types of medications. Medicines that work on the nerve pain cells (such as gabapentin or duloxetine) can be of benefit in many people. A pain management expert is an essential consultant for your husband.