The concept of psoriatic disease: can cutaneous psoriasis any longer be separated by the systemic comorbidities?

Psoriasis is a general inflammatory status in which the skin is usually visibly involved. Recent papers show that several comorbidities, including psoriatic arthritis, metabolic syndrome, cancer, osteoporosis, cardiovascular disease, chronic inflammatory bowel disease etc., are significantly associated with psoriasis. Detecting association between psoriasis and comorbidities, properly evaluate confounders and make a correct distinction among absolute risk, relative risk and clinical relevance is mandatory, before embracing the fact the psoriasis is, in fact, a complex and common international disease.