Coffee allergy
Sensitivity or allergy to coffee.
About coffee allergy
Coffee is made from roasted coffee beans, and true IgE-mediated allergy to drinking coffee is rare. Most unwanted effects from coffee come from caffeine, which is a stimulant and can cause a racing heart, jitteriness, stomach upset or headache in sensitive people; these are pharmacological or intolerance effects rather than an immune-based allergy. Where genuine allergy does occur, it is more often linked to handling green (unroasted) coffee beans, which can cause occupational allergy in workers who inhale the dust.
Caffeine-related symptoms tend to come on within an hour or so of drinking coffee and settle as the caffeine wears off. In the rare cases of true allergy, symptoms usually begin within minutes to two hours and may include an itchy mouth, hives, swelling and, uncommonly, more severe reactions. Occupational coffee-bean allergy more often causes respiratory symptoms such as a runny nose, wheezing or asthma from inhaling green-bean dust, rather than reactions from the drink.
Diagnosis is guided by a careful history and food and symptom diary to separate caffeine intolerance from true allergy, with skin-prick or specific-IgE blood tests arranged through an allergy specialist where a genuine allergy is suspected. Management depends on the cause and usually means reducing or avoiding coffee or caffeine, or, for workers, reducing exposure to green-bean dust. Most reactions are mild, but if any reaction ever involves breathing difficulty, throat swelling or faintness, treat it as an emergency and call 999.
Common triggers
- Coffee and products containing it
Symptoms
- Itching or tingling in the mouth
- Hives, itching or eczema
- Swelling of the lips, face, tongue or throat
- Stomach cramps, nausea, vomiting or diarrhoea
- Wheezing or trouble breathing
- In severe cases, anaphylaxis
Avoidance & management
- Read ingredient labels every time
- Ask about ingredients and cross-contamination when eating out
- Keep the food out of shared cooking areas
- Carry prescribed antihistamines or an adrenaline auto-injector
- Seek emergency help for any severe reaction
Sources & references
Allergy safety: what everyone should know
Mild-to-moderate reaction signs
- Itching, hives or a raised rash
- Swelling of lips, face or eyes
- Tingling mouth, sneezing, runny nose
- Stomach pain, nausea or vomiting
Anaphylaxis — call 999 (UK) or 112 (EU) immediately
- Difficult or noisy breathing, wheeze, persistent cough
- Swelling of the tongue or tightness in the throat
- Dizziness, collapse, pale and floppy (young children)
- Use an adrenaline auto-injector (e.g. EpiPen) at once if prescribed, then call an ambulance even if symptoms improve
Allergy or intolerance? A true allergy involves the immune system and can escalate quickly; an intolerance (e.g. lactose intolerance) is unpleasant but not life-threatening. The symptoms overlap, so self-diagnosis is unreliable.
Getting tested: home-testing kits based on IgG are not diagnostically valid. If you suspect an allergy, ask a GP for referral to an allergy clinic for skin-prick or specific-IgE testing and a supervised food challenge where appropriate.