My son is always sick. He either has a cold, sinus infection, ear infection, or stomach flu. It has been on and off for 2 years, but has been really bad for the past 6 months. He does not eat and hardly drinks. He has barely eaten anything in 5 days this time. This happens each time he gets sick. He is now 2 years, 9 months old and weighs 26 lbs. At one year he was 23 lbs.

I am going to the doctor today to demand they find out what could be doing this to my little guy. This is becoming a cycle. Can you think of anything I should ask for? I am going to request allergy testing, but is there more I need to know? What could cause him to be so sick all of the time? I do have autoimmune conditions, could this have affected him?

I'm glad you have an appointment today. When kids get sick that often, it is wise to look into why. Allergies are a common reason for repeated infections. About 1/3 of kids with chronic ear infections, for instance, have an underlying allergy as the cause. Allergy testing may make good sense.

Environmental toxins -- most notably second-hand smoke -- cause many infections. About 2 million ear infections alone are caused directly by second-hand smoke each year in the US.

Some kids do have underlying immune problems, such as an IgG subclass deficiency, which can be treated if found. Ask your doctor if it is time to look into things like this.

Also, he may have missed out on the Prevnar (pneumococcal) vaccine because of his age. This prevents the most common bacterial causes of respiratory infections including ear infections, sinus infections, and pneumonia. He may be a candidate for the vaccine now.