Antihistamines come in various different forms, which includes tablets, capsules, liquids, syrups, creams, lotions, gels, eye drops and nasal sprays.
They work by blocking the way the substance, histamine, impacts the body. Histamine is usually released when the body detects something harmful, such as an infection. It reacts by making our blood vessels and skin swell, which are two natural defence mechanisms.
But if you have an allergy, your body will mistake something harmless, such as pollen, animal hair or house dust – as a threat and produce histamine. The histamine then triggers an allergic reaction that most commonly involves symptoms such as itchy, watering eyes, a runny or blocked nose or sneezing and skin rashes. Antihistamines prevent this from happening, providing you take them before you’re exposed to the substance you’re allergic to. If taken after your allergy symptoms have been triggered, they can potentially help reduce the severity of the symptoms.