Dermatite Alérgica à Pulga: Quando Uma Mordida Causa Miséria
Alguns animais são alérgicos à saliva de pulgas. Uma única picada de pulga pode desencadear coceira intensa e inflamação da pele.
Flea allergy dermatitis (FAD) is the most common skin disease in dogs and cats. Pets with FAD are hypersensitive to proteins in flea saliva. A single flea bite can trigger an intense allergic reaction lasting weeks. Even pets with very few fleas can suffer severe symptoms. RVC can diagnose FAD and provide effective treatment. Call +853 6677 6611.
Key Points
- FAD is caused by an allergic reaction to flea saliva proteins
- A single flea bite can trigger itching lasting 2-3 weeks
- Symptoms: intense itching, hair loss, red bumps, and secondary infections
- Most common on the lower back, tail base, thighs, and belly
- Diagnosis is based on symptoms and finding flea dirt (flea feces)
- Treatment requires eliminating ALL fleas from the pet AND environment
How FAD Works
When a flea bites, it injects saliva containing allergenic proteins. In sensitive pets, the immune system overreacts, releasing histamine and other chemicals that cause intense itching and inflammation. The reaction is delayed — itching starts hours to days after the bite and continues long after the flea is gone. This is why pets with FAD remain itchy even when you can't find any fleas on them.
Symptoms
Dogs: intense itching over the lower back, tail base, hind legs, and belly. Hair loss, red papules (small bumps), crusting, and darkening of the skin (hyperpigmentation) from chronic irritation. Secondary bacterial infections are common. Cats: small crusted bumps (miliary dermatitis), hair loss on the back and belly, or eosinophilic granuloma complex (lip ulcers, chin swelling, linear plaques on thighs). Cats may also overgroom, causing symmetrical hair loss.
Diagnosis
Diagnosis is based on: 1) Clinical signs consistent with FAD. 2) Finding flea dirt (black specks that turn red when wet — digested blood) in the coat. 3) Response to flea treatment. 4) Intradermal allergy testing or blood tests (IgE) can confirm flea allergy but are rarely needed. Important: even if you don't see fleas, your pet can have FAD. Fleas hide in dense fur and may only be present in small numbers.
Treatment and Prevention
Treat ALL pets in the household with a fast-acting, long-lasting flea product (isoxazolines: Bravecto, NexGard, Simparica, Credelio are excellent choices). Treat the environment: wash bedding in hot water, vacuum thoroughly (including under furniture), and use environmental sprays or foggers if infestation is heavy. For severe symptoms: corticosteroids or antihistamines reduce itching and inflammation. Antibiotics for secondary skin infections. Year-round prevention is essential — even in winter, fleas can survive indoors.
When to See a Vet Immediately
- Intense itching that doesn't improve with basic flea treatment
- Hair loss and skin inflammation, especially on lower back and tail base
- Secondary skin infections from scratching
- Cat with miliary dermatitis or eosinophilic granulomas
- Any pet with suspected flea allergy
- Need guidance on effective flea prevention products
How RVC Can Help
RVC diagnoses and treats flea allergy dermatitis and can recommend the most effective prevention for your pet. Call +853 6677 6611.
This article is for educational purposes only and does not replace professional veterinary advice. If your pet is showing any symptoms, please contact Royal Veterinary Center immediately at +853 6677 6611.