Natural history of peanut allergy and predictors of resolution in the first 4 years of life: A population-based assessment.
BACKGROUND
There are no prospectively collected data available on the natural history of peanut allergy in early childhood. Previous studies of predictors of tolerance development have been biased by failure to challenge high-risk children when IgE antibody levels are high, therefore potentially introducing bias to persistent allergy.


OBJECTIVE
We sought to describe the natural history of peanut allergy between 1 and 4 years of age and develop thresholds for skin prick test (SPT) results and specific IgE (sIgE) levels measured at age 1 and 4 years that have 95% positive predictive value (PPV) or negative predictive value for the persistence or resolution of peanut allergy.


METHODS
One-year-old infants with challenge-confirmed peanut allergy (n = 156) from the population-based, longitudinal HealthNuts Study (n = 5276) were followed up at 4 years of age with repeat oral food challenges, SPTs, and sIgE measurements (n = 103). Challenges were undertaken in all peanut-sensitized children at 1 and 4 years of age, irrespective of risk profile.


RESULTS
Peanut allergy resolved in 22% (95% CI, 14% to 31%) of children by age 4 years. Decreasing wheal size predicted tolerance, and increasing wheal size was associated with persistence. Thresholds for SPT responses and sIgE levels at age 1 year with a 95% PPV for persistent peanut allergy are an SPT-induced response of 13 mm or greater and an sIgE level of 5.0 kU/L or greater. Thresholds for SPT and sIgE results at age 4 years with a 95% PPV for persistent peanut allergy are an SPT response of 8 mm or greater and an sIgE level of 2.1 kU/L or greater. Ara h 2, tree nut, and house dust mite sensitization; coexisting food allergies; eczema; and asthma were not predictive of persistent peanut allergy.


CONCLUSIONS
These thresholds are the first to be generated from a unique data set in which all participants underwent oral food challenges at both diagnosis and follow-up, irrespective of SPT and sIgE results.
Population Health, the Murdoch Childrens Research Institute, Parkville, Australia; Department of Paediatrics, University of Melbourne, Parkville, Australia.
Rachel L
RL
Peters
Population Health, the Murdoch Childrens Research Institute, Parkville, Australia; Department of Paediatrics, University of Melbourne, Parkville, Australia; Department of Allergy and Immunology, Royal Children's Hospital, Parkville, Australia; School of Inflammation and Repair, the University of Manchester, Manchester, United Kingdom. Electronic address: katie.allen@rch.org.au.
Katrina J
KJ
Allen
Population Health, the Murdoch Childrens Research Institute, Parkville, Australia; Melbourne School of Population and Global Health, Centre for Epidemiology and Biostatistics, University of Melbourne, Parkville, Australia.
Shyamali C
SC
Dharmage
Population Health, the Murdoch Childrens Research Institute, Parkville, Australia.
Jennifer J
JJ
Koplin
Population Health, the Murdoch Childrens Research Institute, Parkville, Australia.
Thanh
T
Dang
Population Health, the Murdoch Childrens Research Institute, Parkville, Australia; Department of Paediatrics, University of Melbourne, Parkville, Australia.
Kate P
KP
Tilbrook
Population Health, the Murdoch Childrens Research Institute, Parkville, Australia; Melbourne School of Population and Global Health, Centre for Epidemiology and Biostatistics, University of Melbourne, Parkville, Australia.
Adrian
A
Lowe
Population Health, the Murdoch Childrens Research Institute, Parkville, Australia; Department of Paediatrics, University of Melbourne, Parkville, Australia; Department of Allergy and Immunology, Royal Children's Hospital, Parkville, Australia.
Mimi L K
ML
Tang
Population Health, the Murdoch Childrens Research Institute, Parkville, Australia; Melbourne School of Population and Global Health, Centre for Epidemiology and Biostatistics, University of Melbourne, Parkville, Australia.
Lyle C
LC
Gurrin
D000367:Age Factors; D000485:Allergens / Q000276:immunology; D010367:Arachis / Q000009:adverse effects; D001315:Australia / Q000453:epidemiology; D002675:Child, Preschool; D015897:Comorbidity; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007108:Immune Tolerance / Q000276:immunology; D007073:Immunoglobulin E / Q000276:immunology; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D021183:Peanut Hypersensitivity / Q000453:epidemiology* / Q000276:immunology*; D011159:Population Surveillance; D012307:Risk Factors
D000485:Allergens; D007073:Immunoglobulin E
Peanut allergy; natural history; predictive value of tests; resolution; skin prick test; specific IgE