Natural course and risk factors for persistence of IgE-mediated cow's milk allergy.

OBJECTIVE: To describe the natural course of IgE-mediated cow's milk allergy (IgE-CMA) and to determine risk factors for its persistence in a population-based cohort. STUDY DESIGN: In a prospective cohort study, 54 infants with IgE-CMA were identified from a population of 13 019 children followed from birth. Diagnosis of IgE-CMA was based on history, skin prick test (SPT), and an oral food challenge (OFC) when indicated. Allergic infants were followed for 48-60 months. Families were contacted by telephone every 6 months and asked about recent exposures to milk. OFC was repeated to evaluate for recovery. Clinical characteristics, SPT, and OFC outcomes were compared between infants with persistent IgE-CMA and infants who recovered. RESULTS: Thirty-one infants (57.4%) recovered from IgE-CMA during the study period. Most infants (70.9%) recovered within the first 2 years. Risk factors for persistence on multivariate analysis included a reaction to <10 mL of milk on OFC (or on first exposure as estimated by the guardian, if OFC was not performed) (P = .01), a larger wheal size on SPT (P = .014), and age of ≤30 days at time of first reaction (P = .05). CONCLUSIONS: Resolution occurs in most infants with IgE-CMA. Infants reacting to <10 mL of milk or in the first month of life, and those with a larger wheal size on SPT, are at increased risk for persistence.

Transmission of Panton-Valentine leukocidin-positive Staphylococcus aureus between patients with cystic fibrosis.

Panton-Valentine leukocidin-producing Staphylococcus aureus is an emerging pathogen world-wide, causing necrotizing lung infections in otherwise healthy individuals. We describe 2 episodes of patient-to-patient transmission of Panton-Valentine leukocidin-producing S. aureus, resulting in acute, life-threatening pulmonary complications in patients with cystic fibrosis. Appropriate infection control measures may be warranted to prevent similar episodes.