There are several reasons why children are more likely than adults to get ear infections. Eustachian tubes are smaller and more level in children than they are in adults. This makes it difficult for fluid to drain out of the ear, even under normal conditions. If the eustachian tubes are swollen or blocked with mucus due to a cold or other respiratory illness, fluid may not be able to drain. A child’s immune system isn’t as effective as an adult’s because it’s still developing. This makes it harder for children to fight infections.