Conditions and symptoms
What Is Hypersensitivity? Drug Allergy
Hypersensitivity · say it: hy-per-sen-sih-TIV-ih-teeAlso written: hypersensitivity reaction, drug hypersensitivity, drug allergy
Short answer
Hypersensitivity means the immune system overreacts to something, such as a medicine. It covers allergic reactions from mild rash to severe reactions.
What it means
Hypersensitivity is the medical word for when the body's immune system reacts too strongly to something that is usually harmless, such as a medicine, food or pollen. A drug hypersensitivity reaction can be mild, like an itchy rash, or severe, like anaphylaxis.
Labels often say a medicine is not for people with 'known hypersensitivity' to it or to its ingredients. This means: if you have reacted badly to this medicine, or a closely related one, before, you should not take it again without your doctor's advice. Leaflets also list hypersensitivity reactions so you know which signs to report.
Hypersensitivity is different from a side effect. A side effect, such as feeling sick, can happen to anyone and is not an immune reaction. Hypersensitivity depends on how your own immune system responds.
Where you may see it
- The 'Contraindications' section of medicine labels: 'Do not use if you have known hypersensitivity to...'
- Leaflets under 'Allergic reactions'
- Allergy alerts on hospital and pharmacy records
📄 How it looks on a report
Contraindicated in patients with known hypersensitivity to any component of this product.
🙅 What it does not mean
- It does not mean you are allergic to the medicine. It is a warning for people who already know they react to it.
- Not every reaction listed on a leaflet is hypersensitivity. Many are ordinary side effects.
- A hypersensitivity reaction is not always severe, but any new rash, swelling or breathing problem should be reported.
🎯 Check yourself
Which of these is the right meaning of “Hypersensitivity”?
🗒️ Questions to ask your doctor
💊 Medicines whose labels mention “Hypersensitivity”
Plain-English explanations of each medicine, from its official FDA label.
- Albendazole
an anthelmintic drug, a medicine used to treat infections caused by parasitic worms
- Albuterol
A bronchodilator (a medicine that opens the airways) of the beta-2 adrenergic type. The FDA class is not listed, so this description comes from the label's own wording.
- Alendronate
a bisphosphonate, a medicine that slows the breakdown of bone by blocking cells called osteoclasts
- Allopurinol
a xanthine oxidase inhibitor, a prescription medicine that acts on uric acid
- Amitriptyline
An antidepressant of the tricyclic type
- Amoxicillin and Clavulanate Potassium
A penicillin-class antibacterial combined with a beta-lactamase inhibitor, as the label describes it
- Ampicillin Sodium
a penicillin-type antibacterial medicine
- Apixaban
A factor Xa inhibitor, a blood thinner medicine (anticoagulant)
- Aripiprazole
an atypical antipsychotic medicine
- Artemether and Lumefantrine
an antimalarial medicine, which is a fixed combination of two blood-stage antimalarial ingredients (artemether, an artemisinin derivative, and lumefantrine)
🔗 Read more from trusted sources
- “Hypersensitivity” on MedlinePlus ↗
US National Library of Medicine
- NCI Dictionary definition ↗
US National Cancer Institute: “hypersensitivity”
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General information about a medical word, not advice about your own results. Ask the clinician who ordered the test what it means for you.