How does a bed bug bite occur? - briefly
A female bed bug pierces the skin and injects saliva with anticoagulants to feed, creating a painless puncture that later turns itchy and reddened. The visible welts appear after the insect withdraws its proboscis.
How does a bed bug bite occur? - in detail
Bed bugs locate a host by detecting carbon dioxide, body heat, and skin odor. When a suitable target is identified, the insect climbs onto the exposed skin and inserts its elongated, needle‑like mouthpart, the stylet, into the epidermis. The stylet penetrates the skin surface without breaking it, creating a microscopic channel that is not visible to the naked eye.
Once the channel is formed, the bug injects a small quantity of saliva that contains anticoagulants, anesthetic compounds, and enzymes. The anticoagulants prevent blood clotting, the anesthetic suppresses the host’s immediate sensation, and the enzymes facilitate digestion of the blood meal. Blood is drawn by a pumping action of the bug’s cibarial pump, which creates negative pressure within the feeding tube.
The feeding process typically lasts from five to ten minutes, during which the insect may take several milliliters of blood. After engorgement, the bug withdraws the stylet, leaving a puncture site that may develop a red, itchy welt within a few hours. The reaction varies with individual sensitivity to the salivary proteins.
Key steps in the biting sequence:
- Host detection via CO₂, heat, and odor cues
- Climbing onto skin and probing with the stylet
- Saliva injection containing anticoagulant, anesthetic, and digestive enzymes
- Blood uptake through negative pressure generated by the cibarial pump
- Withdrawal of the mouthpart and formation of a puncture wound
The entire event occurs without the host noticing the bite at the moment, allowing the insect to feed undisturbed. Subsequent skin reactions are a delayed immune response to the salivary proteins introduced during feeding.