Causes. Although doctors don't know what causes ITP, they know that it happens when your immune system -- your body's defense against disease -- doesn't work right. Your antibodies, which are supposed to attack infections, instead mistakenly destroy your blood platelets.
Although not as strong as the Asian monsoon, the cycle is typical of monsoon seasons worldwide. The monsoon season begins on June 15 and ends on September 30, but the storms peak between mid-July and mid-August. On average, about half of Arizona receives about half of its annual rainfall during the monsoon. However, rainfall can vary tremendously between distances of just a few miles.
With this shift in the winds, the monsoon begins in northern Mexico in May. The moisture-laden monsoon air travels north to Arizona and New Mexico, encouraged by the pressure difference between the hot, parched southwestern air and the cooler Mexican air.