Itch Threshold

The pruritic (itch) threshold, or clinical threshold, is the point when a pet begins to experience severe itching and scratching due to a summation of events, each of which contributes independently to the cascade of itchy discomfort your pet feels.

The pruritic thresholds are unique in each animal. The summation effect explains why an animal who is allergic with low-level dermatitis to one or two mold allergens can appear to be completely normal, until she develops a new allergy to fleas, for example.

Taken separately, the flea or mold allergy may not cause her enough discomfort to “scratch,” but the summation effect of the two allergies together may cause her to reach a clinical threshold, where her discomfort manifests in clinically noticeable symptoms; she begins scratching due to excessive itching.