Allergy, anaphylaxis & EpiPenSevere allergy? Know your pen. Use it fast.Anaphylaxis is a severe allergic reaction that can affect breathing and blood pressure within minutes. An adrenaline pen such as an EpiPen is the first treatment, and knowing how and when to use it properly saves lives.Book a GP appointmentCall 07857 761328Anaphylaxis is an emergency. Use your adrenaline pen, then call 999 and say “anaphylaxis”.Same & next-day appointmentsEpiPen technique checkedAllergy clinic referralYou keep your NHS GPAllergy blood test £4021What is anaphylaxis?2Signs to look for3Triggers4Who is at risk5Your appointment6Using your EpiPen7Get help now8FAQs Medically reviewed by Dr Sam R Bandularatne, MBBS, DFMS, MRCGP · GP Partner & GP Trainer · GMC 5208303OUR GP Dundee · Last reviewed November 2026Seen by a GPPen technique checkedTwo in-date pensWritten allergy planStart hereWhat anaphylaxis is, and why speed mattersAnaphylaxis (say “ana-fill-axis”) is the most serious kind of allergic reaction. It comes on quickly and affects the airway, breathing or circulation.Most allergies cause milder symptoms such as sneezing, itchy eyes, a rash or hives. In anaphylaxis the whole body reacts: the throat can swell, breathing can become difficult and blood pressure can fall. It usually starts within minutes of contact with the trigger, and stings often act faster than foods.The treatment is adrenaline, given straight away, into the outer thigh muscle. An adrenaline auto-injector such as an EpiPen or Jext lets you, a family member or a bystander give it in seconds, before the ambulance arrives.It comes on fastUsually within minutes. People often feel suddenly unwell or have a sense that something awful is happening.Think A, B, CAirway, Breathing or Circulation problems are what make it anaphylaxis, not a rash alone.Adrenaline firstAntihistamines and inhalers are not enough on their own. Use your pen first, then other medicines.It can come backSymptoms can return hours later, which is why you always need an ambulance and a hospital check.Back to top ↑Signs to look forSigns of anaphylaxis: think A, B, CAny one of these after contact with a possible trigger means: use the pen now.Airway: swollen throat or tongue, or the throat feels tightAirway: hoarse voice, or difficulty swallowingBreathing: sudden shortness of breath or wheezingBreathing: a cough that won’t stop, or noisy breathingCirculation: dizzy, faint, pale and clammyCirculation: drowsy, confused, floppy (in a child) or collapseSkin signs can be missing. A rash, hives, swollen lips or eyes, tummy pain or vomiting often come first, but in up to one in five reactions there is no rash at all. If in doubt, use your pen: adrenaline is safe to give.At OUR GPFind out what you react to: ALEX allergy profileFor people who have had allergic reactions and want to understand their triggers.A single blood sample tested for a wide range of common allergens, with the results explained.Good to know: a blood test cannot predict how severe a future reaction will be. Always carry your adrenaline pens if you have been prescribed them.See all our fees →£402Alex Allergy Profile · about 20 minutes Book nowBack to top ↑TriggersWhat can cause anaphylaxisFood, medicines and insect stings cause most reactions. Sometimes no trigger is found.GroupExamplesFoodsPeanuts, tree nuts, milk, egg, fish, shellfish, sesame, wheat, soya and some fruitsInsect stingsWasps and bees. Remove a bee sting quickly by any method: speed matters more than howMedicinesSome antibiotics (such as penicillin), anti-inflammatory painkillers, anaesthetic medicines and contrast dyesLatexRubber gloves, balloons, condoms and some medical equipmentOtherExercise after eating certain foods, or no cause found (idiopathic anaphylaxis)Usually milderPets, pollen, house dust mites and mould more often cause hay fever, asthma or eczema than anaphylaxisWho is more at risk of a severe reactionAnyone with an allergy can have anaphylaxis, but a serious reaction is more likely if you:have asthma, especially if it is not well controlledhave had anaphylaxis beforeare a teenager or young adultare allergic to peanuts, tree nuts or shellfishhave heart diseasedon’t have your adrenaline pens with youGood asthma control lowers your risk. If your inhaler use has crept up, or you wake at night with asthma, book a review.Back to top ↑Your appointmentWhat the GP will doAfter a reaction, the aim is to make sure you are protected and ready if it happens again.Go over what happenedWhat you ate, touched or were stung by, how quickly symptoms came on, and what treatment you needed.Check your pens and techniqueYou should have two in-date pens of the right strength for your weight, and know how to use your own brand.Refer you to an allergy clinicSpecialists can confirm the trigger with tests, and some people with sting allergy can have desensitising treatment.Agree a written planAn allergy action plan for home, school or work, plus advice on avoiding your trigger and on asthma control.Back to top ↑Using your EpiPenHow to use your EpiPen properlyRemember: blue to the sky, orange to the thigh. Practise with a free trainer pen so it becomes automatic.1. Grip it in your fistOrange tip pointing down. Keep your thumb and fingers off both ends.2. Pull off the blue capStraight up with your other hand. Don’t bend or twist it.3. Aim at the outer thighHold the orange tip about 10 cm away. You can inject through clothes, but avoid seams, zips and pockets.4. Push in firmlySwing and push the orange tip into the outer thigh at a right angle until it clicks.5. Hold for 3 secondsKeep it pressed firmly in place and count slowly: 1, 2, 3.6. Remove and rubTake it out and rub the area for 10 seconds. The orange cover slides over the needle.Straight after using itCall 999 and say “anaphylaxis”, even if you start to feel betterLie down with your legs raised. Sit up only if breathing is hard, then lie back down. Do not stand or walkUse the second pen after 5 minutes if you are not improving, or straight away if the first one fails to workDon’t stay alone. Give the used pens to the paramedicsRisks and using it safelySide effects are short-livedA racing heart, shaking, feeling anxious, pale or sick usually pass quickly. Not using the pen in anaphylaxis is far more dangerous.Injected a finger or hand?Go to A&E or call NHS 24 on 111 straight away. Never inject into the buttock, hands or feet.Store it properlyKeep it at room temperature in its case, not in the fridge or a hot car. The liquid in the window should be clear, not cloudy or brown.Check the expiry dateExpired pens work less well. Order replacements early and sign up for the maker’s free expiry alerts.Children: hold the child’s leg firmly while you inject. Pen strength depends on weight, so ask us to review it as your child grows. Jext pens and adrenaline nasal sprays are used differently: always follow the instructions for your device. Severe allergy (anaphylaxis) and your EpiPenDownload our anaphylaxis and EpiPen leafletA free two-page guide for patients, families and carers: the signs of anaphylaxis, common triggers, how to use an EpiPen step by step, what to do afterwards, and the risks. Print it for school, work or a relative.PDF · 2 pages · A4 · 234 KBDownload leaflet (PDF)Open to printBack to top ↑Get help nowWhen it can’t waitUse your adrenaline pen, then call 999, if there isswelling of the throat or tongue · a hoarse voice or difficulty swallowing · wheezing or difficulty breathing · feeling faint, very pale or floppy · collapse or loss of consciousnessContact a GP the same day, or NHS 24 on 111 out of hours, ifyou have used an adrenaline pen and been discharged from hospital, you have had a new allergic reaction, you have fewer than two in-date pens, or you are not sure how to use your device.A private appointment is not a substitute for emergency care. If you are unsure, call 999 or NHS 24 on 111.Back to top ↑FAQsCommon questions When should I use my EpiPen?Straight away at the first sign of airway, breathing or circulation problems after contact with your trigger, or if your allergy plan says to. Don’t wait to see if it gets worse. If you are unsure, use it: adrenaline is safe to give. Do I still need to call 999 if I feel better?Yes, always. The pen starts treatment but the effect wears off, and symptoms can come back hours later. You need to be checked by paramedics and in hospital. How long do I hold an EpiPen in place?Hold an EpiPen firmly against the outer thigh for 3 seconds after the click. Other brands differ: a Jext pen is held for 10 seconds. Always follow the instructions for your own device. Can I inject through my clothes?Yes. Inject into the outer thigh through light clothing, avoiding seams, zips, pockets and anything in them. Why do I need two pens?One dose is sometimes not enough, and any device can occasionally fail. UK medicines safety advice is to carry two in-date pens with you at all times. What if I take antihistamines or use my inhaler instead?Antihistamines help itching and hives, and an inhaler can ease wheeze, but neither treats anaphylaxis. Use your adrenaline pen first, then call 999. Are there side effects from adrenaline?A fast heartbeat, shaking, feeling anxious, pale, sick or having a headache are common and short-lived. In anaphylaxis the benefit far outweighs these effects, including in pregnancy and in people with heart problems.Worried right now?If you think someone is having anaphylaxis, use their adrenaline pen and call 999. Out of hours, call NHS 24 on 111 for other worries.Back to top ↑EvidenceWhere this information comes fromThis page follows UK guidance on recognising anaphylaxis and the safe use of adrenaline auto-injectors.NICE Clinical Knowledge Summaries: Angio-oedema and anaphylaxisBNF: Adrenaline (including auto-injector doses and patient advice)BMJ Best Practice: AnaphylaxisBMJ Best Practice: Insect bites and stingsNICE CG134: Anaphylaxis: assessment and referral after emergency treatmentMHRA: Adrenaline auto-injectors (AAIs) safety campaignBack to top ↑Living with a severe allergy?Book a GP appointment to check your pens and technique, arrange an allergy referral and agree a written plan.Book a GP appointmentWhatsApp 07857 761328This page is general information and is not medical advice or a diagnosis. What’s appropriate is a clinical decision made with a GP at your appointment. OUR GP is a trading name of SRS Health Group Limited, regulated by Healthcare Improvement Scotland. All doctors hold a licence to practise with the General Medical Council. Meet our team. We see patients from Dundee, Angus, Perthshire and Fife. More questions? See our FAQs.