RESUMO
Moderate to severe psoriasis is associated with concomitant diseases that may have a significant impact on patients. It is necessary for the treating physician to recognize these concomitant diseases, known as comorbidities, early as they influence the management options. Important comorbidities are psoriatic arthritis, metabolic syndrome, Crohn's disease, depression, and cancer. Patients with severe psoriasis may be at an increased risk for myocardial infarction and this subgroup of patients tends to have a reduced life expectancy. The presence of co-morbid diseases is associated with an increase in concomitant medication, some of which may worsen psoriasis; conversely, systemic treatment of psoriasis with certain drugs may impact the co-morbid conditions. As dermatologists are the primary health-care providers for psoriasis, adequate knowledge of comorbidities helps in choosing the appropriate therapy as well as timely intervention.