Peanut Allergy (PA) is recognised as one of the “big 8” food allergens, accounting for ∼90% of all food-specific allergic reactions. An increase in prevalence of allergic reactions to these allergens, especially peanuts, has risen in recent years. This study looks to analyse the methods used to diagnose PA across 5 European countries and attempt to explain why this increase is happening. Prevalence of peanut allergy was estimated based on publicly available, published scientific literature. Research was conducted on five European countries: UK, Germany, France, Italy & Spain. A meta-analysis was created in order to compare and contrast study results and diagnostic methodologies. These methods were split into 4 categories based on results of the analysis: double-blind placebo-controlled food challenge (DBPCFC), skin prick test (SPT), oral challenge (OC) and self/parent reported (S/PR), and compared across age groups. The analysis showed that less specific diagnostic criteria lead to higher prevalence estimates. Self/parent reported food allergies reached 35% in certain categories (e.g. German adults and UK school-age children); however, when DBPCFC was used in areas with reported high prevalence of peanut allergy, this yielded a 0% prevalence. Data showed that, unlike some food allergies, peanut sensitivity commonly lasts throughout adult life and does not fade. When countries follow strict diagnostic criteria, the prevalence of peanut allergy is consistent throughout. This is an under-researched area despite the high prevalence associated with it. Differences in reported prevalence rates could be due to lifestyle choices, environmental factors, diagnostic improvements/measures and awareness of conditions. There is still little known about food allergies, however, treatments to cure are becoming more available, and the area has received more awareness in recent years.