what is the difference between  perianal & perineal areas
The perianal area (peri- + anal) is a subset of the perineal area. The perineum is an erogenous zone for both males and females. Perineal tears and episiotomy often occur in childbirth with first-time deliveries, but the risk of these injuries can be reduced by preparing the perineum, often through massage.
Perianal refers the area of the body surrounding the anus, and in particular, the skin. The perianal skin is very sensitive and is susceptible to injury and damage from diarrhea, constipation, and disease. Irritation to the perianal area can occur with persistent diarrhea.