A new study indicates that up to 1 in 20 children have food allergies by the age of six, reflecting a prevalence of 5% in the United States. This analysis reviewed 190 studies encompassing more than 2.7 million children in 40 countries. The research, published in JAMA Pediatrics, identified major and minor risk factors associated with food allergies. Significant risk factors included: previous allergic conditions such as asthma and eczema; antibiotic use in the first month of life; a family history of food allergies; late introduction of foods such as egg, fish, and peanuts; and parental racial identity and migration history. Minor risk factors included: male gender; cesarean birth; being a firstborn child; and genetic variations related to the skin barrier. Key Findings: ABC News Senior Medical Correspondent Dr. Tara Narula emphasizes that food allergies are multifactorial, influenced by genetics, environment, and other factors. Although correlations have been established, a direct cause-and-effect link has not been proven. However, experts caution about the limitations of the research, as most of the data comes from high-income countries, and not all studies confirmed allergies through adequate testing. It is emphasized that the early introduction of potentially allergenic foods between 4 and 6 months of age may be crucial to preventing the development of food allergies. Symptoms of food allergies in children: The most common symptoms of food allergies in children include skin reactions, digestive and respiratory problems, which usually appear minutes or hours after consuming the trigger food. Skin symptoms: These are the most frequent and usually manifest as hives (itchy red welts), rashes, swelling of the lips, tongue, or face, and eczema. In babies, they may rub their eyes or show extreme irritability.

Digestive symptoms. These include nausea, vomiting, diarrhea, abdominal pain, and cramps, often mistaken for mild food poisoning. In cases like FPIES (common in infants), severe vomiting and lethargy occur hours later.4

Respiratory and severe symptoms. These include sneezing, nasal congestion, coughing, wheezing, throat tightness, or difficulty breathing. The most serious involve anaphylaxis: dizziness, weak pulse, fainting, or swelling that affects breathing, requiring immediate attention.

How to diagnose an allergy correctly

The correct diagnosis of a food allergy in a child requires a professional medical evaluation, beginning with a detailed medical history. No single test confirms the diagnosis on its own.

Medical history. The first step is to gather accurate information about the symptoms, the time elapsed since ingesting the suspected food, their severity, and duration.

The pediatrician performs a physical exam and asks about the child's diet to identify patterns, such as reactions to milk, eggs, or nuts common in infants.

Initial tests. Skin prick tests are used, where drops of allergens are applied to the skin of the forearm or back, and redness or swelling is observed after 20 minutes. Specific IgE is also measured in the blood to detect antibodies against suspected foods, although positive results need to be correlated with the clinical presentation.

Confirmatory test. The controlled oral food challenge is the gold standard: the suspected food is eliminated and then reintroduced under medical supervision to observe reactions. In clear cases with a suggestive history, positive prick test, and high IgE, it can be omitted, but always in hospital settings due to the risk of anaphylaxis.

Special considerations. Always consult a pediatric allergist; Avoid self-diagnosis or prolonged dietary eliminations without guidance, as these can cause nutritional deficiencies. Symptoms like hives or swelling are more obvious, but eczema requires testing.