How does flea allergy manifest? - briefly
«Flea‑induced allergic dermatitis» presents as intense pruritus, erythema, papules and focal hair loss, typically on the lower back, tail base, abdomen and hind limbs. Secondary lesions such as scabs, crusts or pustules may develop from scratching or biting the affected sites.
How does flea allergy manifest? - in detail
Flea‑induced hypersensitivity is an IgE‑mediated reaction to proteins in flea saliva. The immune response triggers a rapid, intense itching that typically appears within 12–24 hours after a bite.
The skin changes include:
- Localized redness and swelling at bite sites
- Small, raised papules that may develop into pustules or crusts
- Erosions that can coalesce into larger lesions
- Excessive scratching leading to raw, oozing areas
Typical locations are the ventral abdomen, inguinal folds, base of the tail, inner thighs, neck, and muzzle. These regions correspond to areas where fleas commonly attach.
When exposure persists, lesions become chronic. Features of long‑standing disease are:
- Patchy hair loss (alopecia)
- Darkened skin (hyperpigmentation)
- Thickened, leathery plaques (lichenification)
- Permanent scarring
Secondary bacterial infection frequently follows intense scratching. Signs of infection are purulent discharge, foul odor, and increased warmth. Fungal overgrowth may accompany prolonged moisture from exudate.
Systemic effects are less common but may include restlessness, reduced activity, and, in severe infestations, mild anemia due to blood loss.
Flare‑ups correspond with increased flea activity. Seasonal peaks often occur in warmer months, and lesions intensify after re‑exposure to fleas, even if the animal was previously treated.