|MadSci Network: Medicine|
Greetings That was a good question and one that is of great concern right now due to the increase in West Nile Virus. Bites may become infected from excessive scratching allowing bacteria to enter the bite and cause the infection. Other concerns of the mosquito bite are allergic reactions from mild itching and swelling to the more severe swelling and difficult breathing. http://www.mosquito-netting.com/treatment.html Continual scratching may also prolong the symptoms. Why does this happen? Your body contains special cells called mast cells. When they are irritated, such as being scratched, they release all sorts of chemicals. One of these is called histamine. Histamine causes tiny blood vessels to release blood into surrounding tissues. This causes the area to look red, feel hot and become swollen. The blood cells can help fight infection in the tissue, but the swelling can put pressure on nerves, causing more itching or pain. Scratching a mosquito bite releases histamine. Besides causing swelling, histamines sensitize nerves, making sensations such as pain or itching more intense. Scratching actually makes the itching worse. The more you scratch it, the more histamine you release and the more it itches. A trick that I learned is to use your fingernail to press into the center of the bite several times, making a star shaped pattern. This helps disperse the mosquito spit (Yes, the initial itch is caused by mosquito spit.) without releasing too much histamine. The histamine reaction can also be triggered by things you are allergic to. It may just be a yummy strawberry or peanut butter, but if you are allergic, your body mistakenly identifies it as something dangerous. This triggers the histamines, and you get a rash or worse. A histamine reaction in the airway can cause the tissue in your nose, throat and lungs to swell. That makes it difficult to breathe. When that happens, we take something to stop the histamines, an antihistamine. Many medicines for colds and flus contain antihistamines. Some people are so allergic that they have to go to the hospital to control the reaction. http://www.edgerton.org/kidscorner/scratchscience.html Check out the following sites for more information on what happens when we scratch our mosquito bites. There is a wealth of information contained in the following links. www.cyh.com/cyh/kids/detail.html?topic_id=1444&l1=4 - 28k www.pathlights.com/nr_encyclopedia/16pois01.htm www.science.edu.sg/ssc/scinet_all. jsp?type=6&startQid=3565&endQid=3664 - 51k - Jun 19, 2004 Thanks for taking the time to send in a question to the Madsci org. June Wingert Associate Scientist Lexicon Genetics The Woodlands Texas
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