RESUMEN
A total of 122 infants and children up to age 17 (69 males and 53 females) who were referred for food allergy to the Pediatric Allergy and Clinical Immunology Unit were evaluated by complete history, emphasizing the implicated foods, clinical presentation and involvement of various organ systems, physical examination, and prick skin tests to food allergens. Fourteen infants with a history of egg white allergy and positive skin tests to egg white also underwent skin tests (prick and intradermal in 1:100 dilution) to measles-mumps-rubella (MMR) vaccine; 35 children under 3 years old had 41 oral challenges with the suspected foods; and 9 children over 3 years old had 12 oral challenges with the suspected foods. We found that cow milk/humanized milk formula, egg white, soybean, and peanut are the main allergenic foods in the pediatric population. Thirteen children had 13 positive oral challenges: 12 to cow milk/humanized milk formula and one to egg white. Symptoms reproduced by oral challenges included urticarial and erythematous rash, conjunctival itching, angioedema, abdominal pain, vomiting, diarrhea, and rhinorrhea. No anaphylactic shock was reported. Negative skin test has an excellent predictive accuracy for negative oral challenge with the suspected food in children > 3 years old. The negative predictive accuracy of cow milk skin test in children < 3 years was 73%. Positive skin test is not a good predictor of a clinical reaction to food. Oral food challenge performed cautiously in a medical setting is the "gold standard" for diagnosis. MMR vaccine can be safely administered to infants with egg white allergy after skin tests with the vaccine are performed.