Allergic Reaction

Key points

• Reactions triggered by food or insect venom can extend beyond the skin, swelling the lips, tongue or throat.
• Anaphylaxis comes on fast and can involve laboured breathing, collapsing blood pressure, or unconsciousness, so it needs emergency care.
• When inflammation is more widespread, a brief steroid course can be used once antihistamines alone are not enough.

What an allergic reaction looks and feels like

Mild-to-moderate reactions typically involve itching, hives (raised, red welts on the skin), sneezing, watery eyes, or a runny nose. Reactions to food or insect venom can also cause swelling of the lips, tongue, or throat. More severe reactions, known as anaphylaxis, come on quickly and may include difficulty breathing, a sudden drop in blood pressure, or loss of consciousness. Anaphylaxis is a medical emergency: go to the nearest emergency department immediately.

How allergic reactions are treated

For mild reactions, antihistamines settle itching and hives quickly. When inflammation is more significant, widespread rash, facial swelling, or persistent symptoms, a short course of a corticosteroid such as prednisolone helps calm the immune response. Severe or recurrent reactions sometimes call for a broader management plan that may touch on pain management if the reaction causes significant discomfort.

Further reading

• Allergies - NHS
• Allergies and hypersensitivities - Healthdirect