Children with recurrent attacks of sinusitis have often been given repeated courses of antibiotics by their doctor. Tackling their allergy problems can relieve the sinusitis, but the child may still be generally unwell. Common symptoms are tiredness, colic and a pale face with dark rings under the eyes. They may also have itchiness around the anus. These symptoms seem to be a result of the antibiotics, which have disturbed the gut flora, the beneficial bacteria that are normally found in a healthy person's intestine. It is probably an overgrowth of yeast (one- celled fungi) in the gut that causes the problem — these yeast are present in everyone, but their numbers are kept in check by the bacteria present. Children with these symptoms are often helped by a course of the anti-fungal drug nystatin. This is a very safe drug with virtually no side-effects.

Children with allergies to pollen or house-dust mite, or both, are sometimes afflicted with recurrent bouts of sinusitis. Often these children are treated with a course of antibiotics each time, and the antibiotics achieve some partial success, suggesting that an infection is playing its part in the symptoms. However, experience in allergy clinics shows that when these children's allergies are dealt with, their regular bouts of sinusitis often disappear. It cannot be good to dose children with antibiotics regularly and unnecessarily, so if allergy treatment can remove the symptoms instead, this is surely preferable.