Hi I am wondering what the possible causes and treatments
Hello and welcome to Ask A Doctor service.
I have reviewed your query and here is my advice.
IgG deficiency causes are divided into primary and secondary.
Primary is idiopathic that cause is unknown,may be genetic in origin.
Secondary causes of low IgG and IgA deficiency may be aging, malnutrition, cytotoxic drugs, uraemia,liver disease, chronic renal failure, burns, protein losing nephropathy.
Treatments include specific management of infections with antibiotics. Prevention of infections is needed by avoiding polluted water, food, air, etc.
Hope this helps. Let me know if I can assist you further.