What Causes Itchy Prickly Heat Rash On Hands During Summers?

hi from 3 days My skin become very allergic may be because of summer season . I am feeling very itching ,feel like rubbing skin on hands when I do that I observe prickly heat like . initially i faced it on hands then feeling total body itching. very uncomfortable . can I use suncross aqu gel or I have to use any other lotion to get rid of this itching feeling.