5 Things About Psoriasis and Its Complications

August is National Psoriasis Month (or action month, depending on the organization doing the talking), which is aimed at raising awareness about this chronic autoimmune disease affecting more than 8 million Americans. Inflammation causes redness of the skin and silver scaly plaques and can show up on the scalp, elbows, palms, soles, or nails, or be more widespread in severe cases. The persistent itching can have a negative effect on the quality of life. Here are 5 things to know about psoriasis and its complications:

1. Psoriasis can progress to psoriatic arthritis

Left untreated, patients with moderate-to-severe psoriasis could develop psoriatic arthritis (PsA), which affects up to 40% of patients. Similar to rheumatoid arthritis, PsA can cause pain, disability, and permanent joint deformities. Compared with patients with psoriasis who do not have PsA, patients with psoriasis and PsA have greater disease burdens and different treatment patterns. A 2015 study calculated the economic burden of psoriatic disease at up to $135 billion a year.

2. Psoriasis has been linked to some cancers

In particular, certain cancers may be a special concern. A recent meta-analysis found a number of site-specific cancers that seem to carry an elevated risk. Overall, in the 9 included studies of patients with severe disease, there was a significantly elevated risk ratio of 1.22 (95% CI, 1.08-1.39) for all cancer types. By site, cancers that stood out as having particular risk for patients with severe disease include squamous cell carcinoma, lymphoma, and basal cell carcinoma.

3. Psoriasis is more than just itchy skin—it carries risk for other diseases

More severe disease is also associated with more comorbidities. Patients with PsA may have more severe atherosclerotic disease as well as a higher risk of cardiovascular disease, endothelial dysfunction, metabolic syndrome, hypertension, hyperlipidemia, obesity, and diabetes.

4. More psoriasis research is needed

Additional studies are needed because some of the mortality risk behind psoriasis is unexplained, according to a recent paper published in the Journal of the American Academy of Dermatology. Even after adjusting for demographics, smoking, and comorbidities, psoriasis was independently associated with a 1.99-fold increased mortality risk compared with controls (95% CI, 1.01-3.93; P = .047).

5. Use of step therapy is growing alongside rising prescription drug costs

Step therapy, sometimes called “fail first,” requires that patients try the payer’s preferred treatment before the one a physician recommends. The National Psoriasis Foundation has been working to get laws passed at the state level to curb the use of step therapy, saying that treatment delays can hinder care. One recent study said step therapy for patients with PsA was linked to lower odds of treatment effectiveness, mainly due to lower odds of adhering to treatment.