Final answer:
Histamine plays a key role in allergic reactions and inflammation in dogs, causing itching (pruritus) by binding to receptors that stimulate an immune response. Antihistamines and corticosteroid creams are commonly used treatments that mitigate the action of histamine and provide relief from symptoms.
Step-by-step explanation:
The role of histamine in chronic itching in dogs pertains to its function as a mediator of inflammatory responses and allergic reactions. Histamine is released from mast cells upon encountering an allergen or during tissue damage, which leads to various symptoms including pruritus (itching). It binds to the H1 receptor, causing inflammation, itchiness, and in some cases, constriction of the airways. Treatments like antihistamines and corticosteroid creams work by blocking the action of histamine on these receptors or reducing histamine release, consequently reducing the severity of itching and other allergic symptoms.