Changes

Animals typically present with a history of compulsive biting, chewing and licking. Cats may scratch around the head and neck. Signs of fleas and flea dirt may be seen on both dogs and cats.

Animals typically present with a history of compulsive biting, chewing and licking. Cats may scratch around the head and neck. Signs of fleas and flea dirt may be seen on both dogs and cats.

Clinical exam findings depend on the severity of the hypersensitivity reaction and the degree of exposure to fleas. Fleas or flea dirt may be found, but these can be removed by overgrooming. In dogs, low molecular weight hapten and two high molecular weight allergensflea allergic dermatitis usually causes marked pruritus, although individual variation does exist. Lesions are most typically seen on the caudal dorsum, the inner and posterior thighs and the umbilical area

Clinical exam findings depend on the severity of the hypersensitivity reaction and the degree of exposure to fleas. Fleas or flea dirt may be found, but these can be removed by overgrooming in particularly sensitive animals. In dogs, lesions are concentrated along the caudal dorsum, the caudal aspects of the thighs, the ventral abdomen and the cranial antebrachium, but any area may be affected. Within fifteen minutes of receiving a flea bite a papule appears and persits for up to 72 hours, when it forms a crust. However, these lesions may be difficult to appreciate due to the secondary changes that result from self-trauma in response to pruritus. These may include excoriations, erythema, seborrhoea, hyperpigmentation and lichenification or pyotraumatic folliculitis. A mild secondary bacterial folliculitis may also be present.

, but any region may be affected. Within fifteen minutes of receiving a flea bite a papule appears and persits for up to 72 hours, when it forms a crust. However, these lesions may be difficult to appreciate due to the secondary changes that result from self-trauma in response to pruritus. These may include excoriations, erythema, seborrhoea, hyperpigmentation and lichenification. A mild secondary bacterial folliculitis may also be present.

Cats respond to most cutaneous insults in one of four reactions patterns (miliary dermatitis, eosinophilic granuloma complex, head and neck pruritus, symmetrical alopecia).  This is also true in flea infestation and flea allergic dermatitis. Miliary dermatitis is by far the most common presentation in this case, but symmetrical alopecia and eosinophilic granuloma complex may also be seen.

Cats respond to most cutaneous insults in one of four reactions patterns (miliary dermatitis, eosinophilic granuloma complex, head and neck pruritus, symmetrical alopecia).  This is also true in flea infestation and flea allergic dermatitis. Miliary dermatitis is by far the most common presentation in this case, and is typically seen on the caudal dorsum and around the head and neck. Symmetrical alopecia of the inguinal region and the eosinophilic granuloma complex may also be seen.

===Additional Tests===

===Additional Tests===