What determins how big a mosquito bite gets?!

What determins how big a mosquito bite gets?

i was lead on to believe that scratching makes the bite area bigger and spreads some poison that they give u when they bite then one of my best friends told me thats not true so what is it?

Scratching DOES make the bite bigger and itchier. 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 the bigger the bite gets and the more it itches.

I got about 10 mosquito bites on my feet and ankles last night. They felt like they were on fire! I rubbed 1% cortinsone cream into the bites (gently, without scratching!) for about five minutes, and soon they stopped itching completely.