How do fleas bite a person’s skin? - briefly
Fleas pierce the epidermis with needle‑like stylet mouthparts while injecting saliva that contains anticoagulant enzymes. The saliva triggers a localized inflammatory response, resulting in the itchy welts commonly observed.
How do fleas bite a person’s skin? - in detail
Fleas locate a host by detecting body heat, carbon‑dioxide, and movement. Upon contact, the insect climbs onto the skin surface and searches for a suitable feeding site, typically near hair follicles or areas with thin epidermis.
The feeding process begins with the flea’s mouthparts, which consist of a pair of piercing stylets and a sucking tube. The stylets penetrate the stratum corneum and descend through the epidermis to reach the superficial dermal blood vessels. Salivary glands release anticoagulant proteins that inhibit clotting and maintain blood flow. The flea then draws blood through the tube while simultaneously injecting saliva that contains irritant compounds, triggering a localized inflammatory response.
Key steps in the bite mechanism:
- Detection of host cues (heat, CO₂, motion).
- Ascension onto the skin and selection of a puncture site.
- Insertion of stylets through epidermal layers.
- Delivery of anticoagulant saliva.
- Extraction of blood via the sucking tube.
The host’s reaction typically manifests as a small, red, itchy papule. Histamine released in response to the flea’s saliva causes vasodilation and pruritus. Repeated bites may lead to hypersensitivity, resulting in larger welts or secondary infection if the skin is broken.
Understanding each phase of the feeding cycle informs prevention strategies, such as reducing environmental flea populations, maintaining personal hygiene, and applying topical repellents that disrupt the insect’s ability to locate or penetrate the skin.