20% off €35

Code:EXTRA20
Vitamins & SupplementsCBDCollagen & SilicaHair, Skin & NailsShop all Hair, Skin & NailsHair GrowthFunctional MushroomsVitaminsShop all VitaminsMultivitaminsVitamin AVitamin BVitamin CVitamin DVitamin EVitamin KVitamin DrinksMineralsShop all MineralsMagnesiumIronZincCalciumSeleniumChromiumSupplementsShop all SupplementsFibre SupplementsAcidophilus & Friendly BacteriaPeppermint OilGrapeseed ExtractLecithinCollagen & SilicaOmega & Fish OilsPlant Sourced SupplementsSuperfood SupplementsArnicaApple CiderRaspberry KetonesAloe VeraChondroitin & MSMCo Enzyme Q10Evening Primrose OilGarlicGlucosamineGlucomannanSeaweed, Kelps and AquaceuticalsDigestive EnzymesCharcoalWomen's HealthShop all Women's HealthMenopauseMenstrual SupportUrinary Tract HealthPregnancy & ConceptionMen's HealthShop all Men's HealthProstate HealthChildren's HealthConditionShop all ConditionCholesterolAllergy & Hay Fever CareAnxiety SupportBone & Muscle HealthMuscle Support & Joint PainBrain & Memory SupportWomen's HealthMen's HealthChildren's HealthCold & Immune SupportFatigueDigestive HealthHair, Skin & NailsHeart & CirculationLiver CareMood SupportSexual HealthSleep & RelaxationStress ReliefVisionHerbal & Licensed RemediesShop all Herbal & Licensed RemediesRescue RemedyAshwagandhaMilk ThistleGinseng & GuaranaHomeopathic & Flower RemediesShop all Homeopathic & Flower RemediesRescue RemedyVegan Vitamins & SupplementsHolland & BarrettVitabioticsNovominsSolgarNew NordicBetterYouBioglanNatures AidWild NutritionDAMEBuy 1 Get 1 FreePayday Event3 for 2 Mix & MatchBuy one get one 1/2 priceSave up to 1/2 PriceOutletBetter than half price3 for €18Dairy FreeGluten FreeSugar FreeSoya FreeAlcohol FreeSesame Seed FreePalm Oil FreeCelery FreeCereal FreeCrustaceans FreeLion's Mane MushroomApple Cider VinegarReishi MushroomChaga MushroomCollagenCastor OilShiitake MushroomVitamin EAloe VeraMaitake MushroomNew inFood & DrinkVegan Food & DrinkDried Fruit, Nuts & SeedsShop all Dried Fruit, Nuts & SeedsDried FruitNutsSeedsMixesChocolate CoatedManuka HoneyTeas, Coffee & Hot BeveragesShop all Teas, Coffee & Hot BeveragesCoffee & Coffee SubstituteMushroom DrinksTeasMatcha & Green TeaSleep & Relaxation TeaSlimming TeaWomen's Health TeasDrinks & JuicesShop all Drinks & JuicesMultipack DrinksProtein ShakesJuices & Health ShotsNatural Energy DrinksKombuchaSoft DrinksWaterAlcohol Free DrinksKefirSuperfoodsShop all SuperfoodsSuperfood PowdersMoringa PowderSpirulinaGoji BerriesBaobabChia SeedsHealthier SnackingShop all Healthier SnackingProtein BarsLow Calorie SnacksChocolate, Cakes & BiscuitsSavoury SnacksSweet SnacksSnack BarsCrisps & ChipsFlapjacksPopcornFood CupboardShop all Food CupboardCondiments & SaucesApple Cider VinegarSuperfoodsBreakfast CerealsHoney, Jams & SpreadsTinned FoodsRice, Pasta, Pulses & GrainsHoney, Jams & SpreadsShop all Honey, Jams & SpreadsManuka HoneyHoneyNut ButtersJams & ChutneysSpreadsPateBreakfast CerealsShop all Breakfast CerealsCereals, Bran & FlakesGranolaMuesliOats & PorridgeBreakfast BarsCookingShop all CookingCooking IngredientsApple Cider VinegarCondiments & SaucesSoya & Meat AlternativeSoup & Ready MealsRice, Pasta, Pulses & GrainsHerbs, Spices & SeasoningGravy & StockHome BakingShop all Home BakingBaking MixesBreadFlourSweeteners & Sugar AlternativesEgg SubstitutesDairy AlternativesShop all Dairy AlternativesOat, Rice & Hemp DrinksSoya DrinksNut DrinksCoconut DrinksNutritionally Complete FoodHolland & BarrettNaturyaGrenadeNakdPukkaHeath & HeatherManuka DoctorEgmont HoneyHuelPerfectTedBuy one get one 1/2 priceSave up to 1/2 PricePayday Event3 for 2 Mix & MatchBuy 1 Get 1 FreeBetter than half price2 for €6OutletGluten FreeDairy FreeWheat FreeSugar FreeEgg FreeMilk FreeNut FreeSesame Seed FreeSoya FreeCelery FreeApple Cider VinegarLion's Mane MushroomReishi MushroomChaga MushroomNew inSports NutritionProteinShop all ProteinClear ProteinProtein VeganMeal ReplacementsWhey ProteinMass GainersDiet ProteinCaseinSports SupplementsShop all Sports SupplementsSports CollagenBars, Drinks & SnacksShop all Bars, Drinks & SnacksEnergy BarsProtein BarsProtein ShakesProtein SnacksNutritionally Complete FoodMeal Replacement ShakesPre Workout & EnergyShop all Pre Workout & EnergyPre WorkoutAmino Energy PowdersIntra WorkoutKetoPost WorkoutAmino AcidsShop all Amino AcidsBCAAArginineCreatineShop all CreatineCreatine PowderRehydrationShop all RehydrationElectrolytesEnergy GelsVegan Sports NutritionShop all Vegan Sports NutritionVegan ProteinVegan Protein BarsVegan Pre Workout & EnergyVegan Amino AcidsVegan CreatineSports AccessoriesShop all Sports AccessoriesBottles & ShakersFitness GoalShop all Fitness GoalRecoveryMuscle & StrengthLean MuscleEnergy & EnduranceDiet & Weight LossKetoHolland & BarrettOptimum NutritionPrecision EngineeredApplied NutritionMyproteinGrenadeUSNNakdTriActiveSiSSave up to 1/2 PricePayday EventBuy 1 Get 1 FreeBuy one get one 1/2 price3 for 2 Mix & MatchOutletIntro OfferGluten FreeDairy FreeSugar FreeWheat FreeEgg FreePalm Oil FreeMilk FreeSoya FreeSesame Seed FreeCelery FreeVitamin ENew inBeautyAromatherapy & HomeShop all Aromatherapy & HomePure Essential OilsBlended Essential OilsBase & Carrier OilsHolisticSkincareShop all SkincarePremium SkincareFace CareBody CareSun CareTanning & BronzingEye CareLip CareFoot CareHand & Nail CareCBD BeautyWashing & BathingShop all Washing & BathingShampoo & ConditionerBathing AccessoriesShower Gel & Body WashDeodorantDentalHand WashSoapBath Soak & OilBody ScrubBath Bombs & SaltsFeminine CareIncontinence SupportHair CareShop all Hair CareShampoo & ConditionerHair ColouringHair MasksHair Oil & SerumHair Spray, Gel & MousseHair AccessoriesMother & BabyShop all Mother & BabyBaby Skincare & ToiletriesMakeupDr OrganicFaith in NatureNaturtintWeledaTisserandQ+AMiaromaTrilogyWildChilds FarmSave up to 1/2 PriceBuy one get one 1/2 pricePayday EventBuy 1 Get 1 Free2 for €233 for 2 Mix & MatchOutletAlcohol FreeFluoride freeParfum FreePalm Oil FreeDairy FreeGluten FreeVitamin CTea TreeRosemaryHyaluronic AcidVitamin EAloe VeraRosehipLavenderSeaweedSalicylic AcidNew inWeight ManagementSlimming TabletsFat Burners, Binders & Appetite SuppressantsShop all Fat Burners, Binders & Appetite SuppressantsFat BurnersFat BindersAppetite SuppressantsShakes & Weight Management ShotsShop all Shakes & Weight Management ShotsMeal Replacement ShakesDiet Food & DrinkShop all Diet Food & DrinkDiet FoodLow Calorie SnacksSlimming TeaExercise SupportHolland & BarrettGrenadeOptimum NutritionHeath & HeatherPulsinUSNDiabloEat WaterKalloNudie SnacksSave up to 1/2 PriceBuy one get one 1/2 pricePayday EventBuy 1 Get 1 Free3 for 2 Mix & MatchOutletGluten FreeSugar FreeDairy FreeWheat FreeMilk FreeCelery FreeCereal FreeCrustaceans FreeEgg FreeFish FreeApple Cider VinegarNew inNew InTrendingBuy one get one 1/2 priceSave up to 1/2 PricePayday EventBuy 1 Get 1 Free3 for 2 Mix & Match2 for €23OutletBetter than half price2 for €6Shop all Health & WellnessWomen's HealthMen's HealthImmunityJoints, Bones, & MusclesEnergyGut HealthSleep & RelaxationHolland & BarrettDr OrganicFaith in NatureVitabioticsNaturtintOptimum NutritionWeledaPrecision EngineeredApplied NutritionQ+ABuy one get one 1/2 priceSave up to 1/2 PricePayday EventBuy 1 Get 1 Free3 for 2 Mix & Match2 for €23OutletBetter than half priceGluten FreeDairy FreeAlcohol FreeSugar FreeParfum FreeSoya FreeWheat FreeEgg FreeSesame Seed FreeMilk FreeVitamin CApple Cider VinegarTea TreeLion's Mane MushroomHyaluronic AcidVitamin ERosehipAloe VeraLavenderRosemaryNew inArticlesAll articlesHealthFood & nutritionGut healthImmunityJoints, bones & musclesWomen's healthWellnessHair & skinMental wellbeingSeasonalSleep & relaxationSports nutritionRecipesAll recipesGluten freeLow sugarVeganDairy freePodcast
Skip to content

What is an allergy?

A chalk board with no gluten, nuts, milk and egg written on it
1 in 4 people in the UK are affected by allergies – and each year this number is rising. But what actually is an allergy?
1 in 4 people in the UK are affected by allergies – and each year this number is rising – with as many as half being children. But what actually is an allergy?
We often talk about allergies without using the term correctly or knowing exactly what they are. An allergy is defined as the body’s overreaction to a substance it is exposed to, through eating, breathing or via skin contact. Typical substances – called allergens – that might trigger an allergy include pollen, eggs, nuts and gluten (a protein found in cereals such as wheat). In a non-allergic person the body will not react to the allergen. But in the allergic person, the body’s immune system will overreact, creating antibodies. The antibodies remain in the body, ready to react if that person is exposed to the allergen again. This stage is called ‘sensitisation’ and the allergic person remains unaware they have an allergy. The next time the allergic person comes into contact with the allergen the antibodies kick in and cells, including those in the skin, nose, eyes, mouth, throat and stomach produce chemicals including histamine. These chemicals cause the symptoms of allergies – from mild reactions such as sneezing, itchiness, inflammation, tummy ache, vomiting and diarrhoea – to more severe symptoms including swallowing difficulties, shortness of breath, a drop in blood pressure, chest pain and anaphylactic shock.

Do I have an allergy?

The risk of having an allergy is greater if a close relative has or has had an allergy or asthma, if you have asthma, or if you are a child. But how do you know if your symptoms are those of an allergy or of an intolerance, and exactly what the difference is? The term ‘allergy’ originally covered any adverse reaction to an everyday substance, but now is used specifically to define allergic reactions produced by the immune system. Those with food allergies need only a tiny amount of the food to which they are allergic to have a serious reaction. By comparison, the term ‘intolerance’ means that the immune system is not involved, despite unpleasant symptoms such as wind, stomach cramps and diarrhoea. Those with food intolerance can often eat a small amount of that food without problems. Milk, egg, peanut, tree nuts, fish, shellfish, soy and wheat account for 90 per cent of all food-allergic reactions. While many people grow out of allergies to milk, eggs, wheat or soy, allergies to peanuts and shellfish tend to be life-long, with severe symptoms. Tree nut allergy is one of the most common food allergies and is potentially fatal. Tree nuts include walnuts, almonds, hazelnuts, cashews, pistachios and Brazils, but not peanuts, which are actually legumes, not nuts. Skin allergies occur after the skin comes into contact with an allergen such as the metals used for jewellery, fragrances (in everything from shampoos to laundry detergents), latex, chemicals in hair dye, sunscreen, household solvents and even antibiotic creams and ointments. If you think you have allergy or intolerance symptoms, go to your GP to be tested. Typically, a skin prick test or a blood test will be used. If an allergy or intolerance is diagnosed, this site will be able to help you with advice and information.

Related Articles

Sign up for exclusive offers

Plus, get expert advice to support your health & wellness straight to your inbox when you sign up to Holland & Barrett emails.