Hi Podmog
My dd is 16 months old and she has been suffering from numerous chest infections etc since a bad attack of chicken pox at about 5 months. During the summer, after one chest infection had failed to go after several courses of antibiotics, she was referred to our local hospital. They carried out various tests including those for cystic fibrosis and immune deficiencies, although they felt sure that she was suffering from asthma.
When the results came back we were told that she did in fact have an immune deficiency and that is why she had been continuously ill. She is now on low dose antibiotics all the time and we have to go back to have her levels checked again in 6 months.
Since the diagnosis, I have done quite a bit of research and have learnt more about immune deficiencies. I would think it was definitely worth asking your doctor to send you for these tests, even if it is just to rule it out.
If you want to contact me, please ask mumsnet for my email address and I will tell you what I know.
Hope your dd is feeling a bit better this evening.