Antihistamines and allergies - An update

Allergic conditions are increasing globally. The most frequently occurring allergic conditions include atopic dermatitis, allergic rhinitis and asthma. Allergic reactions are immune-mediated and associated with considerable morbidity that impacts on quality of life and poses a socio-economic burden. It is therefore important to identify triggers and to understand the role of the complex immune system. Antihistamines are the most commonly prescribed medicines to treat allergies. Although the efficacy of H1-receptor antagonists is very similar, their pharmacological properties differ and literature suggests that second generation H1 antihistamines are the preferred treatment option. As a custodian of medicine, the pharmacist should have a good understanding of an allergic reaction, how to treat it appropriately and individualise therapy. This review focuses primarily on common IgE-mediated allergic conditions treated with antihistamines.