How do bedbugs cause itching? - briefly
When a bedbug bites, it injects saliva containing anticoagulant and anesthetic proteins that trigger an allergic skin reaction, resulting in a red, itchy welt. The itch arises from histamine release and inflammation at the bite site.
How do bedbugs cause itching? - in detail
Bedbug bites introduce saliva that contains anticoagulants and anesthetic compounds. These substances suppress immediate pain, allowing the insect to feed unnoticed. Shortly after feeding, the host’s immune system recognizes foreign proteins, triggering a Type I hypersensitivity reaction. Mast cells release histamine and other mediators, leading to vasodilation, edema, and the characteristic pruritic wheal.
The itching process unfolds in several stages:
- Initial exposure: Salivary proteins bind to skin receptors, initiating an allergic cascade.
- Mediator release: Histamine, prostaglandins, and leukotrienes increase nerve fiber sensitivity.
- Neural activation: C‑fibers transmit itch signals to the spinal cord and brain, producing the sensation of discomfort.
- Secondary inflammation: Repeated bites amplify the response, creating larger, more persistent lesions.
Individual sensitivity varies; some people develop immediate redness and intense itch, while others experience delayed reactions that appear 24‑48 hours later. Repeated scratching can breach the epidermis, introducing bacteria and leading to secondary infection, which further exacerbates the itch through additional inflammatory pathways.
Effective management targets each component of the reaction: antihistamines block histamine receptors, topical corticosteroids reduce inflammation, and moisturizers restore skin barrier function. Preventing further exposure by eliminating the insects removes the source of the allergenic saliva, halting the cycle of bite‑induced pruritus.