The right test, not just any test.
A test is one input, not the diagnosis. What you are allergic to is decided by your history and your test results read together — which is why the consultation is longer than the test.
What testing actually tells you
- A test does not say "you are allergic". It says your immune system is primed to react to something. Whether that matters depends on your symptoms.
- Skin prick testing takes 20 minutes, is read in the same visit, and feels like a series of tiny scratches — not injections.
- You must stop antihistamines five days beforehand or the test cannot be read.
- Being tested for everything is worse than being tested for the right things. The history decides what gets tested.
Consider testing if
- Symptoms return at the same time every year, or in the same room, or after the same food
- You have taken antihistamines most days for more than a year
- Your asthma is not controlled despite using inhalers correctly
- A child has eczema, recurring wheeze or a reaction after eating
- You have had hives for more than six weeks
- You have been told you are allergic to a medicine but it was never confirmed
Allergy is not one thing
People say "I have an allergy" as though it were a single condition. It isn't. What you react to, how you meet it, and what it does to you are all different — and so is the test.
Breathed in
Inhalant allergy
House dust mite, pollen, mould, cockroach, cat and dog. The commonest kind by far. Shows up as sneezing, a blocked or running nose, itchy eyes, cough or asthma. Tested by skin prick or specific IgE, and the group most likely to respond to immunotherapy.
Eaten
Food allergy
Milk, egg, peanut, tree nuts, wheat, soy, fish and shellfish most often. True food allergy comes on within minutes — hives, swelling, vomiting, sometimes breathing trouble. Slow, vague symptoms hours later are usually intolerance, which is a different problem needing a different approach.
Touched
Contact allergy
Nickel in jewellery, hair dye, cosmetics, rubber, cement, and plants such as Parthenium. The rash appears a day or two after contact, not immediately, which is why the cause is so often missed. Diagnosed by patch testing rather than skin prick.
Prescribed
Drug allergy
Penicillin and other antibiotics, painkillers, and occasionally anaesthetic agents. Worth taking seriously and worth confirming rather than assuming — most people labelled penicillin-allergic in childhood turn out not to be, and carrying the label for life narrows the antibiotics available to you.
Stung
Insect venom allergy
Bee, wasp and hornet stings. Most people get local swelling and that is all. A reaction away from the sting site — widespread hives, faintness, breathing difficulty — is different, needs an adrenaline auto-injector, and is one of the clearest indications for immunotherapy there is.
Frequently mistaken for it
Not actually allergy
Construction and road dust, smoke, strong perfume, cold air and pollution irritate the airway without any immune reaction. So does non-allergic rhinitis. These will not show on a test, do not respond to immunotherapy, and are treated in a completely different way — which is exactly why testing before treating matters.
What we offer, and how long each takes
| Test | What it is | Time |
|---|---|---|
| Skin prick test | A drop of allergen extract on the forearm, pricked through with a fine lancet. Standard aeroallergen and food panel, with positive and negative controls. | 20 minutes, read the same visit |
| Intradermal test | Used selectively when a skin prick test is negative but the history is strongly suggestive — chiefly for drug and venom allergy. | 30 minutes |
| Specific IgE blood test | Measures allergen-specific antibodies in blood. Used when skin testing is not suitable. | One blood draw; report in 2–3 days |
| Component-resolved diagnostics | Measures IgE against individual allergen proteins rather than the whole food — which separates a genuine food allergy from pollen-food cross-reaction. | One blood draw |
| Patch test | For contact dermatitis — a different disease from immediate allergy. Patches are worn and read over subsequent visits. | 48–96 hours, 2–3 visits |
| Spirometry | Lung function, with reversibility testing where the airways look narrowed. | 20–30 minutes |
| Supervised challenge | The reference standard for food and drug allergy, with dose escalation under observation and emergency treatment on hand. | 3–6 hours |
Skin prick testing
What it actually feels like
Drops of purified allergen extract are placed in a grid on the inside of your forearm — or on the back, for small children. Each drop is pricked through with a fine plastic lancet that barely breaks the surface. It is a quick pinch, not an injection. There is no needle into a vein and no blood.
Two extra drops always go on: a positive control containing histamine, which should react, and a negative control, which should not. Without both, results cannot be read honestly — a point worth knowing when comparing clinics.
You then wait about fifteen to twenty minutes. Where you are allergic, a raised pale bump surrounded by redness — a wheal and flare — appears and itches. The itch is more annoying than the test. Each wheal is measured in millimetres against the controls, and the results are gone through with you before you leave.
Reading results
A wheal of 3 mm or more larger than the negative control is treated as positive. Between 1 and 2 mm is usually negative and interpreted alongside your history. The likelihood of true clinical allergy rises with wheal size — but only the likelihood.
Sensitisation is not the same as allergy
A positive test shows that your immune system has made IgE antibodies to something. It does not, on its own, mean you will react when you meet it. Plenty of people test positive to foods they eat happily every week.
This is why a test result handed over without a consultation is close to useless, and occasionally harmful — it leads to foods being removed from a child's diet for no reason. If a clinic tests you against a long panel and sends a report without sitting down and reading it against your story, you have been sold a test rather than a diagnosis.
Which medicines to stop, and for how long
Antihistamines suppress the skin's ability to react, and a suppressed skin gives a false negative. This is the single commonest reason a testing appointment is wasted.
| Stop for | Medicine | Commonly sold in India as |
|---|---|---|
| 5 days | Cetirizine, Levocetirizine, Fexofenadine, Loratadine, Desloratadine, Bilastine, Rupatadine, Ebastine | Cetzine, Alerid, Okacet · Levocet, Teczine, Xyzal · Allegra, Fexova · Alaspan · Deslor · Bilofix · Rupanex · Ebast |
| 48 hours | Chlorpheniramine, Pheniramine, Hydroxyzine, Diphenhydramine, Promethazine | CPM, Piriton · Avil · Atarax · Benadryl · Phenergan |
| 5–7 days | Herbal and Ayurvedic preparations that blunt skin reactivity | Liquorice (mulethi), green tea extract, St John's wort, feverfew, saw palmetto |
Two things people miss
Hidden antihistamines
Most Indian cold, cough and sinus combinations contain an antihistamine even though the box does not lead with it — Sinarest, D-Cold, Cheston Cold, Coldarin, Vicks Action 500, and the great majority of cough syrups. So do most over-the-counter sleep aids and several anti-vomiting medicines. If you have taken anything for a cold in the last five days, tell us.
What you should not stop
Continue your inhalers, nasal steroid sprays, montelukast, and every medicine you take for anything else — blood pressure, diabetes, thyroid, heart. Stopping an asthma inhaler before an allergy test is dangerous and achieves nothing. If you are on a beta-blocker, tell us before testing rather than stopping it yourself.
If you genuinely cannot stop antihistamines
Some people cannot — severe chronic urticaria is the usual reason. Say so when you book. We will plan specific IgE blood testing instead, which is unaffected by antihistamines because it measures antibodies in blood rather than a skin response.
When blood is better
When a blood test is the right choice
Specific IgE blood testing is not a lesser option — it is the better option in defined situations: extensive eczema or dermographism leaving no clear skin to test; an inability to stop antihistamines; a history of severe anaphylaxis where skin testing carries more risk than it is worth; very young infants; and any patient on medication that cannot safely be paused.
Component-resolved diagnostics goes a step further. Rather than measuring IgE to whole peanut, it measures IgE to the individual peanut proteins — and a raised level to one particular protein is a far more reliable marker of genuine peanut allergy than the whole-extract result. The same approach separates a true hazelnut allergy from pollen-food syndrome, where someone with hay fever gets a tingly mouth from raw hazelnut but can eat it roasted without trouble. That distinction changes what a family has to do for years.
A word on what we don't offer
IgG food intolerance panels
You will see these advertised widely — a blood test against sixty or two hundred foods, returning a colour-coded list of things to avoid. Allergy societies worldwide advise against them, because IgG to a food indicates exposure to that food, not allergy to it. A person who eats rice daily will have IgG to rice. The result reads as a diagnosis and is in fact a dietary diary.
The harm is not the money. It is the months of unnecessary elimination, the nutritional risk in children, and the genuine allergy that goes undiagnosed while the family avoids the wrong ten foods. We do not offer them, and if you have already had one, bring it — it is worth going through what it does and does not tell you.
What patients ask about testing
Does it hurt?
A skin prick test is a series of quick pinches on the forearm, roughly like the scratch of a fingernail. Children tolerate it well. There is no injection and no blood. The itch where you react is the uncomfortable part and it settles within an hour.
How long will I be at the clinic?
Allow about 45 to 60 minutes for a first visit with testing. Most of that is the consultation — the test itself takes about twenty minutes including the wait, and results are discussed with you in the same visit.
From what age can a child be tested?
Skin prick testing can be done in infants where it is genuinely indicated, and is routine from toddler age. The panel is chosen to fit the child and the question being asked, rather than testing everything possible.
Will I get results the same day?
Skin prick results, yes — read, measured and explained before you leave, with a written summary. Specific IgE blood tests take two to three days, and we will go through the report with you rather than sending it by message alone.
Do I need a referral?
No. You can book directly. If you have been seeing a family physician, ENT surgeon or dermatologist for this problem, bring their notes — and with your permission we will write back to them, because continuity matters more than territory.
My skin test was negative but I am clearly reacting to something. What now?
That happens, and it is a real clinical situation rather than a dead end. The possibilities include an allergen not on the standard panel, a non-IgE mechanism, a drug or additive reaction, or a condition that mimics allergy. The next step is usually targeted blood testing, sometimes a supervised challenge, and always a closer look at the history.
I would rather do three tests that answer a question than thirty that produce a list. If you arrive with a report from somewhere else, bring it — reinterpreting an existing result is often more useful than repeating it.