There are two main kinds of irritations: acute and cumulative.
Everyone knows the effects of a violent attacks on the skin such as a burn from fire or boiling water or a corrosive agent. In these cases a painful redness is experienced. This will progressively diminish if the attack was not too severe. This is acute irritation.
Generally speaking, work subjects one's hands to multiple slight attacks during the course of the day. Cleaning materials, industrial oils, soil and cement are all examples. As the interval between these contacts decreases, their effect accumulates until irritation as severe as in acute irritation is evidenced. There is, however, a natural tendency to underestimate this situation.