DISCUSSION AND OUTCOMES
The patient had had colostomy 2-year before to treat a colonic
perforation due to a complication following aortic abdominal aneurysm.
On further questioning, she reported mild psoriasis for approximately 10
years without specific treatment, but using topical steroids
occasionally. In fact, several small psoriatic papules and plaques were
present in other sites, including lower limbs and the back. The
diagnosis of psoriasis following Koebner phenomenon was made.
Koebner phenomenon (KP), also known as isomorphic response, refers to
the occurrence of psoriatic lesions on healthy skin as a consequence of
any trauma. It means that, if patient is already affected by psoriasis,
may develop new lesions of the same kind (isomorphic means “same
morphology”) after traumatic stimuli, including tattoo, burns, surgery
and wounds. Psoriasis is frequently involved in KP, as well as lichen
planus, vitiligo and cutaneous lupus erythematosus.
The risk of peristomal skin damage has been reported, including irritant
dermatitis, due to the chemical injury from the stoma output (stool), or
a mechanical injury after stripping or adhesive removal, or allergic
contact dermatitis for sensitization to latex, rubber, colophony,
contained in the adhesive of the colostomy bag.