Why does a cat itch when it has fleas? - briefly
«Flea saliva» contains anticoagulants that provoke an allergic skin reaction, leading to intense irritation. The cat’s scratching attempts to dislodge the parasites and alleviate the inflammation.
Why does a cat itch when it has fleas? - in detail
Fleas inject saliva containing anticoagulants and proteins each time they bite a cat. The foreign proteins trigger an immune reaction, prompting the release of histamine and other inflammatory mediators. Histamine binds to sensory nerves in the skin, producing the characteristic itching sensation.
The cat’s immune system may develop a hypersensitivity to flea saliva. In sensitised individuals, even a few bites generate a pronounced pruritic response, while non‑sensitised cats exhibit only mild irritation. Repeated exposure amplifies the allergic cascade, leading to chronic scratching.
Mechanical damage also contributes to discomfort. Flea mouthparts penetrate the epidermis, creating micro‑wounds that expose nerve endings. Continuous biting results in clusters of puncture sites, often visible as small red papules or crusted lesions. These lesions become focal points for further irritation.
Excessive grooming in response to itch can cause secondary problems:
- Hair loss in localized areas
- Self‑inflicted abrasions or wounds
- Bacterial or fungal infections secondary to broken skin barrier
Effective control requires eliminating the ectoparasite, treating the allergic inflammation, and restoring skin integrity. Antiflea medications remove the source of saliva, while antihistamines or corticosteroids mitigate the immune‑mediated itch. Topical antiseptics and wound care address any secondary infections, allowing the epidermis to heal and reducing the cat’s urge to scratch.