The most common type of ear infection (otitis media) affects the middle ear, the space between the eardrum and the inner ear. The middle ear is usually filled with air but it can fill up with fluid (during a cold for example) and ear infections happen when bacteria, viruses or fungi infect the fluid and cause swelling in the ear. Ear infections are common in childhood and can be extremely painful causing a considerable amount of distress. Chronic otitis media is when ear infections keep recurring, for example glue ear is a type of chronic otitis media. Otitis media usually reoccurs several times during childhood years. One third of children will have six or more episodes of otitis media by the time they are seven years old. The condition occurs less often as the child gets older. It would be unusual for children over the age of seven to be affected by further episodes (NHS Choices, 2012m). Complications of middle ear infection are now less common than they were in the past. However, it can be a serious problem; otitis media with effusion (glue ear) is the most common cause of hearing impairment in childhood (NICE, 2011). Symptoms vary with time and age, hearing loss usually resolves over several weeks or months, but may be more persistent if in both ears, may lead to educational, language and behavioural problems.
Ear infections are often linked to colds or otherproblems of the respiratory system. However, some reports link ear infections to food allergies (Hurst, 1998; Aydogan et al., 2004; Doner et al., 2004). Researchers from Georgetown University in the US examined the role of food allergy in ear infection in 104 children with recurrent ear problems (Nsouli et al., 1994). The children were tested for food allergies and those who tested positive excluded that particular food for 16 weeks, then reintroduced it. Results showed that 78 per cent of the children with ear problems also had food allergies, the most common allergenic foods were cow’s milk (38 per cent), wheat (33 per cent), egg white (25 per cent), peanut (20 per cent) and soya (17 per cent). 86 per cent of these children responded well to eliminating the offending food, and of these, 94 per cent suffered a recurrence of ear problems on reintroducing the offending food.
A different approach was taken in a Finnish study of 56 children with cow’s milk allergy and 204 children without cow’s milk allergy. These researchers examined the occurrence of ear infection in children known to have cow’s milk allergy. Results showed that 27 per cent of those with the allergy suffered from recurrent ear infections compared to just 12 per cent of those who did not have the allergy (Juntti et al., 1999). It was concluded that children with cow’s milk allergy experience significantly more ear infections.
Dr John James of the Colorado Allergy and Asthma Centres in the US suggests that food allergies can cause inflammation in the nasal passages and lead to the build-up of fluid in the middle ear, but he acknowledges that the link between food allergy and ear infection may be hard to prove (James, 2004). A recent review stated how a large body of epidemiologic evidence now supports a role for allergic rhinitis (allergic inflammation of the nasal airways) as a possible cause of otitis media. Evidence also supports a role for histamine (a compound that triggers the inflammatory response) in both conditions (Skoner et al., 2009). The authors of this study say that given the strong likelihood of allergy as a risk factor for otitis media, allergic rhinitis patients should be evaluated for otitis media and vice versa.
In 2009 the American Dietetic Association reported that for infants, breastfeeding is associated with a reduced risk of otitis media (along with a reduced risk of gastroenteritis, respiratory illness, sudden infant death syndrome, necrotising enterocolitis, obesity and hypertension. They say that exclusive breastfeeding provides optimal nutrition and health protection for the first six months of life and breastfeeding with complementary foods from six months until at least 12 months of age is the ideal feeding pattern for infants (James et al., 2009). More studies are needed to examine the relationship between food allergy and ear infection but the possibility of cow’s milk allergy should be considered in all cases of ear infection, particularly in children.