Can a Peanut Allergy Develop at Age 50?
Yes, peanut allergy can develop at age 50, though it is less common than childhood-onset disease. Over 17% of adults with peanut allergy report onset in adulthood, representing approximately 800,000 US adults who developed their allergy after age 18 1.
Epidemiology of Adult-Onset Peanut Allergy
The current prevalence of peanut allergy among US adults is 2.9%, with 1.8% having convincing IgE-mediated peanut allergy 1. While the majority of peanut allergies begin in childhood (typically by age 2-7 years) 2, adult-onset cases represent a significant and often under-recognized phenomenon.
Adults who develop peanut allergy after age 18 show distinct clinical patterns compared to those with childhood-onset disease:
- Only 58.9% of adults with adult-onset peanut allergy report having a physician diagnosis, compared to 75.4% of those with childhood-onset disease 1
- Adults with adult-onset peanut allergy are significantly less likely to carry epinephrine (44% vs 56% in childhood-onset) 1
- Despite lower epinephrine prescription rates, approximately 1 in 5 adults with peanut allergy—regardless of onset timing—report food allergy-related emergency department visits within the past year 1
Clinical Presentation and Risk
The clinical manifestations of peanut allergy in adults mirror those in children and can be life-threatening:
- Skin symptoms (urticaria, angioedema) occur in 89% of reactions 3
- Respiratory symptoms (wheezing, throat tightness, dyspnea) occur in 52-70% of reactions 3, 4
- Gastrointestinal symptoms occur in 32-40% of reactions 3, 4
- Cardiovascular symptoms occur in up to 35% of cases 4
The primary danger in peanut allergy is laryngeal edema, which accounts for most life-threatening reactions, while hypotension is less common 2.
Critical Management Implications for Adult-Onset Cases
All adults with suspected new-onset peanut allergy at age 50 require:
- Immediate referral to an allergist-immunologist for confirmatory testing (skin prick test and/or peanut-specific IgE) 4
- Prescription of two epinephrine autoinjectors (0.3 mg for adults) to carry at all times 4
- Development of an anaphylaxis emergency action plan 4
- Education on strict avoidance of peanuts and potential cross-reactive foods 4
Important Caveats
Adult-onset peanut allergy is frequently under-diagnosed and under-treated 1. The lower rates of physician diagnosis and epinephrine prescription in adult-onset cases represent a dangerous gap in care, given that emergency department visit rates are equivalent regardless of age of onset.
Unlike childhood peanut allergy where approximately 20% of patients achieve natural tolerance, peanut allergy that develops in adulthood is generally considered permanent 5, 6. There is no current evidence suggesting adults who develop peanut allergy later in life have any likelihood of spontaneous resolution.
Asthma is a significant risk factor for fatal food-induced anaphylaxis, and delayed epinephrine administration increases mortality risk 4. This makes proper diagnosis and emergency preparedness particularly critical in adult-onset cases.