12 Types of Arthritis and How They Differ

3. Psoriatic Arthritis - When Skin and Joints Collide

Psoriatic arthritis affects approximately 30% of individuals with psoriasis, a chronic skin condition characterized by red, scaly patches, though joint symptoms can sometimes precede skin manifestations. This inflammatory arthritis belongs to a group called spondyloarthropathies and presents unique challenges due to its diverse clinical presentations and potential for affecting multiple body systems. Unlike rheumatoid arthritis, psoriatic arthritis often affects joints asymmetrically and can involve the spine, causing inflammation in the sacroiliac joints and vertebrae. The condition is characterized by five distinct patterns: asymmetric oligoarticular (affecting few joints), symmetric polyarticular (similar to rheumatoid arthritis), distal interphalangeal joint involvement, arthritis mutilans (a severe, deforming type), and spondylitis (spinal involvement). Patients frequently experience enthesitis, inflammation at the sites where tendons and ligaments attach to bones, particularly affecting the Achilles tendon and plantar fascia. Dactylitis, or "sausage digits," represents another hallmark feature where entire fingers or toes become swollen and painful. The presence of nail changes, including pitting, ridging, and separation from the nail bed, often provides important diagnostic clues. Treatment typically involves a combination of medications targeting both skin and joint symptoms, including methotrexate, biologics, and targeted synthetic DMARDs.