For just on two years now I have been experiencing infections on and off approximately once a month. Initially it was thought that I had a problem with my sinuses. I had surgery to remove a polyp successfully removed the polyp apart from a small piece at the bottom of my sinus that couldn't be reached. Even after this surgery I am continually getting infections. The sinus surgery was a year ago now.

I have had chest x-rays, MRI of my head and neck, a significant number of blood tests and the only item that shows up is that I have an enlarged lymph node in my neck (approx 1.8 - 2cm). I had an ultrasound on my neck and they reported that while the lymph node was enlarged there was nothing abonormal about it. I have seen an allergist, a haematologist and a naturopath. As yet no one has been able to assist.
The last infection that I had was last week and I was interested to note that my tongue went a green color. I have also noticed that I continually have an itchy scalp. Does anyone have any thoughts as to what might be making me so susceptible to infections?