The majority of children outgrow egg allergy. One review reported that 70% of children will outgrow this allergy by 16 years. In subsequently published longitudinal studies, one reported that for 140 infants who had challenge-confirmed egg allergy, 44% had resolved by two years. A second reported that for 203 infants with confirmed IgE-mediated egg allergy, 45% resolved by two years of age, 66% by four years, and 71% by six years. Children will be able to tolerate eggs as an ingredient in baked goods and well-cooked eggs sooner than under-cooked eggs. Resolution was more likely if baseline serum IgE was lower, and if the baseline symptoms did not include anaphylaxis.

In countries in North America and western Europe, where use of cow's milk based infant formula is common, chicken egg allergy is the second most common food allergy in infants and young children after cow's milk. However, in Japan, egg allergy is first and cow's milk second, followed by wheat and then the other common allergenic foods. A review from South Africa reported egg and peanut as the two most common allergenic foods.

Incidence and prevalence are terms commonly used in describing disease epidemiology. Incidence is newly diagnosed cases, which can be expressed as new cases per year per million people. Prevalence is the number of cases alive, expressible as existing cases per million people during a period of time. Egg allergies are usually observed in infants and young children, and often disappear with age (see Prognosis), so prevalence of egg allergy may be expressed as a percentage of children under a set age. One review estimates that in North American and western European populations the prevalence of egg allergy in children under the age of five years is 1.8-2.0%. A second described the range in young children as 0.5-2.5%. Although the majority of children develop tolerance as they age into school age years, for roughly one-third the allergy persists into adulthood. Strong predictors for adult-persistent allergy are anaphylactic symptoms as a child, high egg-specific serum IgE, robust response to the skin prick test and absence of tolerance to egg-containing baked foods. Self-reported allergy prevalence is always higher than food-challenge confirmed allergy.

For all age groups, a review of fifty studies conducted in Europe estimated 2.5% for self-reported egg allergy and 0.2% for confirmed. National survey data in the United States collected in 2005 and 2006 showed that from age six and older, the prevalence of serum IgE confirmed egg allergy was under 0.2%.

Adult-onset of egg allergy is rare, but there is confirmation of cases. Some were described as having started in late teenage years; another group were workers in the baking industry who were exposed to powdered egg dust.

A pseudoallergy is a condition named for its similar presentation to a true allergy, though due to different causes.

It may be due to alterations in the metabolism of histamine.

It can be the cause of some forms of food intolerance.