Intake recommendations for iodine and other nutrients are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board (FNB) at the Institute of Medicine of the National Academies (formerly National Academy of Sciences) [2].
Answer. The ear canal has very delicate skin; even a hair may cause itching in the ear. So no wonder itching or irritation is a common complaint from the hearing aid user who comes in for a follow up visit.
The ear canal can be blocked from the outside by an excessive buildup of ear wax. It can also be blocked from inside the ear drum due to an infection. Some conditions such as nasal allergies and asthma may increase nasal mucous production in the sinuses and can cause fluid buildup in the Eustachian tube.