My two-year-old son has had a string of ear infections for which he has had to take antibiotics. After each course, he invariably picks up another infection. Have the antibiotics lowered his immune system?

No - immune system responses don't change because an antibiotic has been prescribed, even repeatedly. But neither have they eradicated the infections. It's probably best to have a specialist ENT (ear, nose and throat) opinion to find out why they are recurring. There may be a structural problem in the ear or in the Eustachian tube leading from the back of the throat to the inside of the eardrum. Ask your doctor about further investigations - and to test for deafness, too.

I am a fit, 25-year-old man who exercises regularly. But in the past few years, I've become concerned because, when I stretch, most of the joints in my lower body tend to make a cracking sound. This includes ankles, knees, thigh and toes, and recently my shoulders joined in, too. Should I be concerned ?

Cracking joints are nothing to worry about as long as you don't have pain in them, they don't stiffen or seize up, and they don't give way or swell up. All you are hearing is the cartilage inside the joint or a ligament beside the joint slapping against the bony surface. We all have cartilage and ligaments - some are more audible than others. The noises are not a sign of impending arthritis. However, if you develop pain, stiffening or swelling in your joints, consult your doctor.

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