skin fissure skin fissure a skin fissure is a cutaneous condition in which there is a linear-like cleavage of skin, sometimes defined as extending into the dermis. it is smaller than a skin laceration. schematic image comparing a skin fissure to an erosion and an ulcer. the surface of the knuckles of a hand with xeroderma, showing skin cracking (generalized skin fissuring). generalized a skin area on which there are many skin fissures is called cracked skin, and is most commonly a result of skin dryness. ichthyosis is a genetic disorder where there is often severe skin cracking.