Psoriatic Arthritis: What You Need to Know
The five types of PsA, its distinguishing features like 'sausage digits' and nail pitting, and the many modern treatment options available.
Psoriatic arthritis is a chronic disease with inflammation of the skin and joints. Often psoriasis appears first, but joint pain can precede skin changes, which may show up on the elbows, ears, scalp, stomach, and around the genitals. According to the National Psoriasis Foundation, 10 to 30 percent of people with psoriasis develop psoriatic arthritis.
There are five types: symmetrical (many joints), asymmetrical (few joints), spine involvement, whole-digit or toe swelling (dactylitis), and a destructive, deforming type called arthritis mutilans. Risk factors include having psoriasis, family history, middle age (30s to 50s, though it can occur earlier), the HLA-B27 gene marker (with spine involvement), and stress. Trauma or infection may trigger it in genetically predisposed people.
Distinguishing features include swelling of entire fingers or toes ('sausage digits'), spinal involvement (spondylitis) or sacroiliitis, nail pitting or ridging, and enthesitis, inflammation where tendons and ligaments attach to bone (such as Achilles tendonitis, epicondylitis, or plantar fasciitis). Chest wall irritation (costochondritis) can also occur. Diagnosis involves a thorough exam of joints, tendons, and nails, imaging (X-ray, ultrasound, MRI), lab tests including HLA-B27, and sometimes joint fluid analysis.
There is no cure, but there are many treatments to help you live a full life. Options include NSAIDs (naproxen, ibuprofen), DMARDs (methotrexate, sulfasalazine), steroids, and biologics that block inflammatory chemicals, TNF inhibitors like etanercept (Enbrel), adalimumab (Humira), golimumab (Simponi), certolizumab pegol (Cimzia), and infliximab (Remicade). Newer agents include ustekinumab (Stelara), secukinumab (Cosentyx), apremilast (Otezla), bimekizumab (Bimzelx), ixekizumab (Taltz), risankizumab (Skyrizi), and upadacitinib (Rinvoq). These raise infection risk, so screening for tuberculosis and hepatitis B and C is important.
PsA can affect more than the joints, the eyes, lungs, GI tract, and aorta can be involved, and there is an increased risk of heart disease. Lifestyle helps: an anti-inflammatory diet, a healthy weight, stress reduction, gentle exercise like swimming and yoga, and possibly more vitamin D. Because the emotional impact of skin disease and joint restriction can affect mood, self-esteem, and intimacy, a strong support network of family, friends, clinicians, and a therapist is crucial. Learn more at the National Psoriasis Foundation (psoriasis.org) and the Arthritis Foundation (arthritis.org).
Dr. Maggie Cadet, MD