Patient guide · Allergy and Clinical Immunology
Skin prick tests, first-line IgE-mediated allergy testing — fast, cheap, accurate.
Skin prick testing (SPT) is the first-line diagnostic test for IgE-mediated allergy — food, aeroallergen, insect venom and drug allergy. 20 minutes for a full panel, delivered by a consultant allergist with immediate results.
Why patients choose us
- 01
The right hands
A consultant allergist who tests you, reads you and writes your plan — one clinician, one answer.
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Answers the same visit
Panel applied, read at 20 minutes, interpreted against your history — you walk out with a plan.
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Independent, and free
We are paid by no clinic, so the recommendation is impartial and costs you nothing.
Key facts
Skin prick testing at a glance.
The six things worth knowing before you scroll further — definition, timing, who runs it, what a positive means, how it complements blood testing, and the safety net that must be in place.
- 01
Definition
The IgE-mediated allergy skin test — a small drop of allergen extract pricked into the skin to look for a specific IgE response.
- 02
20-minute test
A full aeroallergen or food panel is read at 15–20 minutes — you leave with your results the same visit.
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Consultant allergist-led
Applied and interpreted by a consultant allergist, alongside your clinical history — never a technician alone.
- 04
Positive = wheal ≥ 3 mm > negative control
A wheal at least 3 mm greater than the saline negative control, with a positive histamine control, defines a positive test.
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Complements specific IgE blood testing
SPT and serum-specific IgE (ImmunoCAP, ISAC) are complementary — used together when history and skin results diverge.
- 06
Adrenaline auto-injector readiness required
Skin prick testing is safe in expert hands, with adrenaline, oxygen and resuscitation equipment immediately to hand.
How it works
From consultation to plan — what happens, in order.
One consultant allergist from first history to written allergy-action plan — most patients complete the pathway in a single visit.
Phase 1 · Before your test
Consultation and antihistamine hold
Phase 2 · On the day
Panel, reading and interpretation
Phase 3 · After
Structured plan and follow-up
- 01
Before
Allergy consultation
A consultant allergist takes a detailed history — triggers, reactions, timing, comorbidities and family history.
- 02
Before
Antihistamine hold (5–7 days)
Antihistamines suppress the wheal and must be stopped 5–7 days before testing; other medications are reviewed on a case-by-case basis.
- 03
On the day
SPT panel applied
Drops of standardised allergen extracts are placed on the forearm and pricked into the skin with a sterile lancet.
- 04
On the day
15–20 minute reading
You wait 15–20 minutes for the wheal and flare to develop — no discomfort beyond mild local itch.
- 05
On the day
Wheal + flare measurement
Each site is measured in millimetres against saline negative and histamine positive controls.
- 06
On the day
Interpretation vs clinical history
Results are only meaningful alongside your history — sensitisation is not the same as clinical allergy.
- 07
After
Structured plan
A written plan covering avoidance, rescue medication, adrenaline auto-injector where indicated, and onward immunotherapy referral.
Typical end-to-end: a single visit. Follow-up as clinically indicated.
What it shows
What a skin prick panel can identify.
The allergens SPT is designed for — with the systemic-reaction pathway called out separately.
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House dust mite
The commonest indoor aeroallergen — perennial rhinitis, asthma and atopic eczema drivers.
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Cat + dog dander
Furry-animal sensitisation, with practical avoidance and immunotherapy options where indicated.
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Grass + tree pollen
Seasonal rhinoconjunctivitis — the mainstay of hayfever diagnosis and immunotherapy selection.
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Peanut / tree nut
Peanut, hazelnut, cashew, walnut, almond, brazil nut and pistachio — with component-resolved follow-on if needed.
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Egg + cow’s milk
The commonest childhood food allergens — with tolerance tracking and reintroduction planning.
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Wheat
IgE-mediated wheat allergy — distinct from coeliac disease and non-coeliac gluten sensitivity.
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Wasp / bee venom
After systemic reactions to insect stings — the gateway to venom immunotherapy assessment.
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Red flag: systemic reaction during testing — immediate adrenaline
Any systemic reaction during SPT triggers immediate intramuscular adrenaline and full resuscitation protocol.
Next steps
What happens after the panel is read.
The eight most common next steps — from avoidance and antihistamine to adrenaline training, sublingual and subcutaneous immunotherapy, and MDT review.
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Allergen avoidance plan
Written, practical avoidance guidance — home, school, workplace and travel — tailored to the confirmed allergen.
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Antihistamine daily
Second-generation, non-sedating antihistamine as first-line pharmacotherapy for rhinitis and urticaria.
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Nasal corticosteroid
Intranasal steroid for moderate to severe allergic rhinitis — the most effective single agent.
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Adrenaline auto-injector prescription + training
Prescription, device training, allergy-action plan and school or workplace letter where indicated.
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Sublingual immunotherapy (SLIT)
Daily under-the-tongue tablets or drops for grass, tree pollen and house dust mite — home-delivered after first dose.
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Subcutaneous immunotherapy (SCIT)
Weekly clinic injections for venom, aeroallergen or unresponsive rhinitis — the gold standard for venom allergy.
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Structured allergy follow-up
Scheduled review to track response, refresh the action plan and reissue adrenaline devices before expiry.
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Multi-disciplinary team review
Joint review with respiratory, dermatology, ENT or paediatrics for complex or overlapping presentations.
Red flags
When SPT should be deferred or done differently.
The nine situations that change the plan — either delaying the test, switching to blood-based IgE, or ensuring full resuscitation-ready cover.
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Anaphylaxis during testing
Immediate intramuscular adrenaline, oxygen, IV access and transfer — a full resuscitation-ready environment is mandatory.
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Recent uncontrolled asthma
SPT is deferred until asthma is controlled — FEV1 typically ≥ 70% predicted before proceeding.
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Beta-blocker use (relative contraindication)
Beta-blockade can blunt the response to adrenaline in the event of anaphylaxis — reviewed and, if possible, held.
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Pregnancy (relative contraindication for venom SPT)
Venom SPT is generally deferred in pregnancy unless the risk of untreated venom allergy outweighs the risk of testing.
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Dermatographism (invalid results)
Non-specific weal formation on any pricking makes SPT unreadable — serum-specific IgE is used instead.
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Extensive eczema
Widespread active eczema at the forearm test site invalidates SPT — blood-based testing is preferred.
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Latex allergy
Latex-free gloves, tourniquets and equipment throughout — history flagged before entering the testing suite.
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Severe cardiovascular disease
Risk-benefit reviewed with the referring physician — venom SPT in particular may be deferred.
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Post-anaphylaxis mast cell tryptase not done
A serum tryptase within 1–4 hours of a suspected anaphylactic episode is a key diagnostic — reordered if missed.
Reading your report
A skin prick report can look intimidating. It isn’t.
Whatever the finding, the report keeps to the same four parts.
A quiet reminder
Sensitisation is not the same as clinical allergy — history is what turns the numbers into a diagnosis.
If you would like us to talk you through your results before your follow-up, just ask.
- 01 Header
Indication and history
Your details, the reason for testing, and the clinical history that shapes interpretation of every wheal.
- 02 Technique
Panel, controls and medication hold
Which allergen panel was applied, the saline and histamine controls, and confirmation of antihistamine hold.
- 03 Findings
Wheal size in millimetres, each allergen
Allergen-by-allergen wheal and flare in millimetres, flagged against the 3 mm positivity threshold.
- 04 Impression
The conclusion — read this first
Sensitisation profile mapped onto clinical history, with the concrete next step — avoidance, medication, adrenaline or immunotherapy.
Recognised by major UK insurers
Cover depends on your policy and clinic; we confirm with your insurer before booking.
Frequently asked
Everything we get asked about skin prick tests.
Quick answers on what SPT is, which allergens are tested, whether it hurts, medication hold, blood-based alternatives and turnaround.
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What is a skin prick test?
A skin prick test (SPT) is the first-line diagnostic test for IgE-mediated allergy. Drops of standardised allergen extract are placed on the forearm and pricked into the skin with a sterile lancet. A wheal at least 3 mm greater than the saline negative control at 15–20 minutes indicates sensitisation.
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What allergens can be tested?
Aeroallergens (house dust mite, cat, dog, grass, tree, weed, moulds), foods (peanut, tree nuts, egg, milk, wheat, soy, fish, shellfish, sesame, fruit, latex), insect venoms (wasp, bee) and selected drugs (penicillin, local anaesthetic). Panels are tailored to your history.
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Does it hurt?
No. The lancet does not draw blood and is not painful. Positive sites are mildly itchy for an hour or so. Antihistamine can be taken after the test to settle any residual itch.
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Do I need to stop my antihistamines?
Yes — stop antihistamines for 5–7 days before the test. They suppress the wheal and can produce false-negative results. Nasal steroids, montelukast and asthma inhalers can continue as normal.
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What is the difference between SPT and specific IgE blood testing?
Both measure IgE-mediated sensitisation. SPT is faster, cheaper and slightly more sensitive; specific IgE blood testing (ImmunoCAP, ISAC) is used when SPT is invalid (dermatographism, extensive eczema, antihistamine dependence) or when component-resolved diagnostics are needed.
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How quickly do I get results?
Immediately. The panel is read at 15–20 minutes and interpreted in the same visit against your history, with a written plan issued the same day.
Sources
The guidance behind this guide.
- British Society for Allergy and Clinical Immunology. Standards of care and skin prick testing guidance.
- European Academy of Allergy and Clinical Immunology. Position papers and testing standards.
- American Academy of Allergy, Asthma & Immunology. Practice parameters.
- NICE. Anaphylaxis: assessment and referral after emergency treatment (CG134).
Reviewed 2026-07-30 by Pulse Atlas Editorial Board, . Next review 2027-07-30. Estimated reading time 4 minutes.
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In practice, in London
Getting skin prick tests sorted in London, without the guesswork
With skin prick tests, the London question is usually about report turnaround and the radiologist reading it — not whether the scan is available. Waiting lists on the NHS for skin prick tests vary widely by borough and by how the GP letter reads. Privately in London, we can normally offer a slot inside the same week, sometimes within 48 hours if there’s a cancellation. The difference isn’t clinical quality — the consultants are frequently the same faces you’d see on the NHS — it’s the calendar.
A typical private booking for skin prick tests in London starts with a consultant conversation — sometimes in person on Harley Street or Marylebone, sometimes on video if that suits better. Any imaging or diagnostics happen at a nearby CQC-registered facility, and reports usually land within 24 to 72 hours. The whole loop, from first call to written report, is often done inside a fortnight. For skin prick tests specifically, the difference between a routine report and a sub-speciality read is where private care earns its keep.
The value of going through a concierge for skin prick tests isn’t access — anyone with an insurer or a credit card can get a private appointment in London. The value is knowing which consultant reads this particular presentation best, which unit turns reports around fastest, and which pathway won’t hit a dead end if the findings point somewhere unexpected.