The most common reactions are itchy rashes (including hives). Sometimes there can be asthma, and very rarely, anaphylaxis. The most frequent allergic reactions are to antibiotics, sulfas, aspirin, quinine, frusemide, indomethecin ( and other ant-inflammatory drugs), oral anti-diabetic and anti-malarial medications.
The chemical food dyes employed in tablets, capsules and liquid medications can result in allergic reactions, customarilly with rashes, occasionally a cough or wheeze.
The chemical preservatives used in medications (e.g. injections, including insulins) can be a problem – headaches, lethargy and asthma being the most common manifestations. Preservatives are employed in creams for the skin, and drops and ointments for the eyes.