23/03/2024
Addressing Flea Allergy Dermatitis in Canine Patients
Case Presentation:
A 2-year-old Mix breed Male Dog visited our clinic exhibiting signs of distress, including itching and hair loss. Upon examination, fleas were discovered on the back, accompanied by scaling, hair loss on the lumbosacral region, and evident puritis.
: Flea Allergy Dermatitis or Alea bite hypersensitivity
Clinical Signs:
Classic clinical signs are papulocrustous lesions distributed on the lower back, tailhead, and caudal and inner thighs. Dogs may be particularly sensitive in the flanks, caudal and medial thighs, ventral abdomen, lower back, neck, and ears. Common secondary lesions include areas of alopecia, erythema, hyperpigmented skin, scaling, papules, and broken papules covered with reddish brown crusts.
Pathophysiology:
Flea Allergy Dermatitis arises from a hypersensitivity reaction to flea saliva proteins. When feeding, fleas inject saliva that contains a variety of histamine-like compounds, enzymes, polypeptides, and amino acids that span a wide range of sizes (40-60 kD) and induce Type I, Type IV, and basophil hypersensitivity reactions. Flea-naive dogs exposed intermittently to flea bites develop either immediate (15 minutes) or delayed (24-48 hours) reactions, or both, and detectable levels of both circulating IgE and IgG
Treatment:
Management of Flea Allergy Dermatitis involves a multi-faceted approach:
1. Flea Control: Implementing rigorous flea control measures is paramount. Several available insecticides provide excellent elimination of established flea infestations on both dogs and cats, including afoxolaner (dogs only), dinotefuran, fipronil, fluralaner (dogs only),imidacloprid, indoxacarb, lotilaner, nitenpyram, sarolaner, selamectin, and spinosad.
2. Symptomatic Relief: Anti-inflammatory medications, such as corticosteroids or antihistamines, can help alleviate itching and inflammation.
3. Addressing Secondary Infections: If present, secondary bacterial or yeast infections should be treated with
appropriate antibiotics or antifungals.
4. The combination of fipronil/(S)-methoprene or other adulticidal/ovicidal products has demonstrated activity against adult fleas and provides prolonged residual ovicidal activity, thus reducing the potential for genetic selection of resistance.