The relevance of the Gell and Coombs classification of allergic reactions has been questioned in the modern-day understanding of allergy, and it has limited utility in clinical practice.

During sensitization, the IgE antibodies bind to FcεRI receptors on the surface of tissue mast cells and blood basophils.

However, about 4-12 hours after antigen exposure, a cough and wheezing may persist in the patient, along with swelling and redness of the skin.

This is known as the late-phase hypersensitivity reaction which can last from approximately 1-3 days and is caused by the release of additional mediators from the mast cells and basophils.

Treatment usually involves adrenaline (epinephrine) because it counteracts anaphylaxis by increasing blood flow and relaxing bronchial muscles that block one’s airways.