My son gets sick so often could he have primary inmunodeficiency? His dr. Says is normal all the time but hes sick 3 weeks in one month and one hes ok

Immunedeficiency. Although illness in children is frustrating, it is a good sign that their immune system is working and becoming more mature. If the infections persist, require hospitalization or need IV antibiotics, then you definitely need to have further evaluation with an immune specialist. To be safe, see an immunologist for testing....It might just calm your fears and it never hurts to have a doctor follow.
Boost his immunity. 1. Probonix probiotics: 1 dropperful daily 2. Vitamin D3 about 2000 IU/day if he is >2 yrs old 3. Have him play outside daily for 20-30 minutes 4. Avoid milk products (butter and heavy cream are safe) 5. Zinc drops (1-2 with meals) once daily when he is sick Your son should catch less infections, and recover much faster with these.
Immunodeficiency. I'm not sure how old your son is, or what sorts/severity of infections he has. See the "10 warning signs of primary immunodeficiency" described by the jeffrey model foundation. http://www.info4pi.org/aboutpi/index.cfm?section=aboutpi&content=warningsigns it would not hurt to have an immunologist evaluate your son if you still have concerns.
It is possible. You did not say how old your son is but infants/toddlers do get many upper respiratory infections during the winter months. If he is older or having them during other times of the year there could be something wrong with his immune system . As a general rule if your son is growing well he is probably fine. If symptoms persist seek further evaluation.
Immune system check. You can ask your pediatrician to check your son for Immune globulin levels and cell function tests. These are blood tests. If these tests are normal, you need to check for possible causes of recurrent infections such as exposure to sick children in day care or school, hand washing hygiene, as well as his diet.
Frustrating. The average kid is well for the 3 months after birth, then starts having 5-7 respiratory and 2-3 diarrheal illnesses /yr to age 5.At school age this declines some. If your kid was not hospitalized with an infection requiring IV antibiotics by age 6 mo,it is unlikely he has a treatable immune deficiency. Some can have more infections with a selective IgA deficiency but we have no treatment for this.