A rash can be itchy, especially if it's caused by a bug bite. Ever wonder what actually causes the itch? The immune and nervous system play a role in that itchy sensation. Skin receptors alert the immune system of a threat, such as in the case of a bug bite, and the immune response causes the itchiness. That annoying discomfort is a sign that the immune system is working to keep the body healthy.
Anti-coagulant
When a mosquito stabs your skin, it deposits an anti-coagulant that keeps your blood in that area from clotting. The anti-coagulant frequently causes the initial itching, which may signal the unwitting host to swat the bug away.
Histamine
Some people don't react at all to the anti-coagulant. They begin to itch as a reaction to their immune systems' natural release of histamine as a response to the threat. Histamine causes inflammation in the area of the bite to accommodate antibodies that rush to the scene to fight off potentially harmful bacteria. In addition, the swelling puts pressure on the nerve cells, causing more itchiness.
Complications
Bugs carry fungi and bacteria on their bodies, pathogens that can be harmful to humans. Bacteria transmitted by a bug can enter a break in the skin caused by itching, which can lead to a more severe allergic reaction or an infection. Mosquitoes and other blood-feeding arthropods are dangerous vectors that transport life-threatening viruses, such as the West Nile virus, according to the Centers for Disease Control. A bug bite could also cause a severe, life-threatening allergic reaction called anaphylaxis.
Treatment
If you've been bitten, wash the area with soap and water three times a day until symptoms subside. If itching persists, apply an antihistamine cream or calamine lotion on the rash. Get emergency help if any signs of anaphylaxis develop. See a doctor if itchiness lasts longer than seven days.
References
- MayoClinic.com: Warfarin side effects: Watch for dangerous interactions
- Mosby's Dictionary of Medicine, Nursing & Health Professions ; Mosby; 2008
- CDC.gov: Information on Arboviral Encephalitides
- Louisiana Department of Health and Hospitals: Two New Confirmed Cases of West Nile Virus
