Dear Dr. Roach: I ate some tilapia last night, and within an hour, I had nausea and a headache, vomiting a few hours later, and now diarrhea. What do you think is going on?

— V.P.

Answer: I would be interested if you felt any sensation of warmth on your face or neck or any flushing, as your symptoms are highly suggestive of a foodborne illness called scombroid poisoning. It is most common after tuna, mackerel or bonito but can come on after eating other fish as well, including tilapia. The fact that it began so soon after eating a compatible fish is suggestive of the diagnosis.

Scombroid is the most common foodborne illness from seafood. Scombroid happens if the fish is not stored at a cold enough temperature (at any time) after being caught. This is why you should refrigerate cans of tuna after opening them.

In addition to the flushing sensation, headaches, nausea, and vomiting, people with a scombroid toxicity can get rashes on their face, neck and upper chest. Sometimes they get burning or itching around their mouth.

If the symptoms aren’t gone before the condition is suspected, then an antihistamine tablet, such as diphenhydramine (Benadryl), can help relieve the symptoms. If there are stomach or intestinal troubles, a different type of antihistamine, such as famotidine (Pepcid), can have an added benefit. If the vomiting and diarrhea are severe, intravenous fluids may be necessary, although my experience is that most cases are more mild than this.

Physicians who make the presumptive diagnosis of scombroid poisoning should contact their local public health authorities to identify where the contamination occurred and help prevent other cases. Scombroid poisoning is vastly underreported.

I was recently in the hospital for a hip fracture and was discharged with oxycodone. I’ve been taking it for about two weeks after stopping morphine in the hospital (the dosage being 2.5 mg twice daily), but I am worried about withdrawal. I know two people who got very ill after suddenly stopping pain medication.

— J.S.B.

Answer: Withdrawal from opiates happens when people who are physiologically dependent on opioids suddenly stop taking them. A person can become physiologically dependent in as little as three weeks, or even shorter if they had been taking opioids in the past. Opioid withdrawal is very unpleasant, with abdominal symptoms (nausea, cramps, diarrhea, vomiting, etc.) and agitation being the most common symptoms.

The main way of avoiding withdrawal is to not stay on opioids too long. Changing from a long-acting opiate like oxycodone to a shorter-acting one may help. Using non-opioid pain relievers to minimize the need for opioids will also help. I have sometimes tapered down the dose slowly to try to prevent withdrawal; however, the dose you are on is already quite low, so the likelihood of withdrawal is small.

I do want to emphasize that it’s important to get off these drugs. Recent studies have shown that 25% or more of people who start taking opioids chronically after a hip fracture continue to take them for months or years, and opioids are not good long-term pain medications for most people.

Contact Dr. Roach at ToYourGoodHealth@med.cornell.edu.