Nettle allergy
Skin reaction (urticaria) from stinging nettles.
About nettle allergy
Stinging nettles produce a rapid skin reaction, but this is largely a direct irritant and urticarial effect rather than a classic delayed allergy. The plant's tiny hairs act like miniature needles, injecting substances including histamine and other irritant chemicals into the skin on contact. This causes an almost immediate stinging, itching and a raised nettle rash (a form of contact urticaria), which is why the reaction appears within minutes rather than after a day or two. Almost anyone can be stung; it does not require prior sensitisation.
The reaction shows as itchy, raised white or red bumps and weals at the site of contact, usually the hands, arms or legs after brushing against the plant, along with a burning or tingling feeling. It typically settles within a few hours, though the itch can linger. Unlike delayed allergic contact dermatitis, it does not usually blister or become scaly, and it tends not to spread far beyond the area touched. Repeated exposure does not generally make people more allergic in the way true contact allergens do.
Most nettle stings need no medical attention and ease on their own; washing the area, avoiding scratching, and a cool compress or over-the-counter antihistamine or soothing cream can help. See your GP if the reaction is unusually widespread, keeps returning, or is accompanied by swelling of the lips, face or throat or any breathing difficulty, which would be uncommon and needs urgent assessment.
Common triggers
- Nettle and products containing it
Symptoms
- Red, itchy rash (contact dermatitis)
- Dry, cracked or scaly skin
- Blistering or weeping in severe cases
- Burning or stinging where skin met the trigger
Avoidance & management
- Avoid skin contact with the trigger
- Wear gloves or use barrier creams
- Choose products labelled free from the allergen
- Rinse skin promptly after contact
- Use emollients or prescribed steroid creams
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.