What are pimples or allergic rashes?

Itch vs irritation: An allergic skin reaction is often associated with itching and usually has no pus.. Depends on the immune mechanism , it should lasts from hours to no more than a week without further contact. Pimples at your age usually occur around the mouth and are probably hormonally related. Pimples don't itch and there is also a white head associated with it.