DEAR DR. DONOHUE: Last year my 6-year-old daughter was diagnosed with exercise-induced anaphylaxis. I am a nurse and had never heard of it. Luckily, I took my daughter to a pediatric immunologist, who diagnosed her immediately.

Whenever she eats a special brand of chicken nuggets and then exercises, her eyes swell almost shut and she starts wheezing. If she eats the nuggets but doesn’t exercise, she has no reaction.

I thought this might help others who have strange symptoms that have gone undiagnosed. My daughter now carries emergency medications with her at all times. – M.S.

ANSWER: Anaphylaxis (ANN-uh-fuh-LAK-siss) is serious business. It’s often seen consequent to an extreme allergic reaction. An example is a penicillin-allergic individual who accidentally gets a shot of penicillin. That person can experience a cascade of responses – flushing, itching, closing up of the throat, airway spasm, choking, breaking out in hives, swelling of the face and tongue, and a profound drop in blood pressure. If the situation isn’t corrected quickly, death can ensue.

Exercise, unbelievable as it sounds, can bring on an anaphylactic reaction. The reaction doesn’t have to have all the above features, but even a modified reaction has to be managed with care and promptness.

Exercise alone can trigger the response. Or it can come on when exercise is coupled with the prior ingestion of a particular food. Frequently implicated foods include shellfish, nuts, celery, wheat and milk.

Your letter might be the answer to some people’s puzzling symptoms. Thanks for telling the story.

DEAR DR. DONOHUE: I am knock-kneed – at least I think I am. My knees almost touch when I stand. I am told I have knock-knees. I am writing because I have just started a running program and wonder if this is going to cause trouble. I have not been active until now, so I haven’t had any problems. – R.W.

ANSWER: When people stand, the centers of their knees should line up with the centers of their feet. Knock-knees are knees that turn toward each other, like they are trying to kiss one another.

They can create problems for runners. Leg and hip anatomy is out of plumb. When the feet strike the ground, there’s going to be exaggerated stress on the leg and hip, so there is a possibility that running could get you into trouble.

If they can’t, then you might have to switch from running to biking or swimming.

DEAR DR. DONOHUE: I am a 41-year-old woman. I exercise five days a week. I lift weights and do aerobics. I have been experiencing a clicking noise in my joints – my knees, shoulders, fingers, toes and ankles. I cannot make a move without a few joints clicking. They are not painful, but it is embarrassing. What is this about? – D.M.

ANSWER: If the joints don’t hurt and if they are not restricted in their motion, then the clicking noises are not usually a sign of trouble.

Tendons gliding over bones can make such noises. So can changes in the pressure within joints.

In the future, if you develop pain, consult a doctor.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475.