What Is Psoriatic Arthritis?
Psoriatic Arthritis (PsA) is a chronic inflammatory arthritis that occurs in people with psoriasis — a skin condition causing red, scaly patches. In India, about 1 in 3 people with psoriasis develops psoriatic arthritis, yet many go undiagnosed because joint pain is not always associated with their skin condition.
Psoriatic arthritis is part of the spondyloarthritis family of diseases and can involve joints, spine, entheses (attachment points of tendons and ligaments to bone), and nails.
Symptoms of Psoriatic Arthritis
- Joint pain and swelling — often asymmetrical (one side worse than the other), unlike RA which is symmetrical
- Dactylitis — “sausage digit” — entire finger or toe is swollen, not just one joint. Highly characteristic of PsA.
- Nail changes — pitting (small depressions in the nail), onycholysis (nail separating from nail bed), and nail discolouration. These are strong clues to PsA.
- Enthesitis — pain at attachment points: heel pain (Achilles tendinitis, plantar fasciitis), elbow pain (lateral epicondyle)
- Spine involvement — back pain and stiffness, especially morning stiffness (similar to ankylosing spondylitis)
- Psoriasis — red scaly skin patches, often on elbows, knees, scalp, and behind ears. The skin disease may precede, accompany, or follow joint symptoms.
Why PsA Is Often Missed in India
In India, psoriasis patients frequently visit dermatologists for their skin, while joint pain goes to orthopaedics. Neither specialist may connect the two. If you have psoriasis and develop joint pain — especially in fingers, toes, heels, or the lower back — you need a rheumatologist assessment specifically for PsA.
Diagnosis
No single test diagnoses PsA. The CASPAR criteria combine skin/nail psoriasis, dactylitis, enthesitis, inflammatory joint symptoms, and negative RF (PsA is usually seronegative — RF is negative). Imaging with X-ray, ultrasound, and MRI helps confirm and assess severity. RF and anti-CCP are typically negative in PsA, distinguishing it from RA.
Treatment of Psoriatic Arthritis
NSAIDs and Conventional DMARDs
Mild joint disease is treated with anti-inflammatory drugs and conventional DMARDs: methotrexate (especially effective for the skin component), leflunomide, and sulfasalazine.
Biologics — TNF Inhibitors
For moderate-severe PsA, TNF inhibitors (adalimumab, etanercept, infliximab, certolizumab) are highly effective for both joints and skin. Indian biosimilars (Exemptia, Etacept) are available at significantly lower cost.
IL-17 and IL-23 Inhibitors
Secukinumab (IL-17 inhibitor) is particularly effective for PsA, including spine disease and nail involvement. Ixekizumab and guselkumab are newer options. TB screening before starting biologics is mandatory in India.
JAK Inhibitors
Tofacitinib and upadacitinib are oral options for patients who fail or cannot tolerate biologics.
Skin and Joint Treatment Together
The ideal is to use a therapy that treats both skin and joints simultaneously. Methotrexate helps the skin more than the joints. Biologics and JAK inhibitors are effective for both. Coordination between your rheumatologist and dermatologist is ideal.
FAQs About Psoriatic Arthritis
Can PsA occur without obvious psoriasis?
Yes. In about 15% of cases, joint symptoms appear before the skin condition. Psoriasis may only be in hidden areas (scalp, umbilicus, natal cleft) that patients don’t notice.
Does PsA cause joint damage?
Yes — especially destructive forms like arthritis mutilans can severely damage joints if untreated. Early treatment prevents damage.
Written by Dr. Keerthivardhan, Rheumatologist, NIMS Hospital Hyderabad.