Type I hypersensitivity

<p>Type I hypersensitivity (or immediate hypersensitivity), in the <a href="/facts/Hypersensitivity/j2AWmqCD">Gell and Coombs classification</a> of allergic reactions, is an <a href="/facts/Allergic_reaction/dYAVosh8">allergic reaction</a> provoked by re-exposure to a specific type of <a href="/facts/Antigen/9JlAernG">antigen</a> referred to as an <a href="/facts/Allergen/bnM4cttq">allergen</a>.  Type I is distinct from <a href="/facts/Type_II_hypersensitivity/zaDMNcly">type II</a>, <a href="/facts/Type_III_hypersensitivity/DJmeS5HU">type III</a> and <a href="/facts/Type_IV_hypersensitivity/yftfcJR5">type IV</a> hypersensitivities. 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.
</p><p>Exposure may be by <a href="/facts/Ingestion/VIsgnlnA">ingestion</a>, <a href="/facts/Inhalation/eB5VlguF">inhalation</a>, <a href="/facts/Injection_(medicine)/fvkH58gk">injection</a>, or direct contact.
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Type I hypersensitivity open-in-new

Type I hypersensitivity