Allergies can start at any age. Infants and small children may be allergic to milk products or eggs, and the allergies may go away as they get older. Sometimes allergies seem to go away then come back. Older adults can suddenly become allergic to something they’ve been exposed to all of their life with no problems. Sinus allergies can block the drainage pathways of the sinuses. This can lead to chronic sinus infections or ear infections. These chronic infections can lead to thickening in the sinus passages. Allergies can cause sinuses to swell and form polyps. Polyps can block nasal passages, leading to further infection. Sometimes surgery is required to correct the sinus damage caused by allergies, and to help eliminate further infection.