What is Dactylitis?

Psoriatic arthritis (PsA) often begins in the distal joints, those farthest away from the core of the body, such as the interphalangeal joints in the fingers and toes. The disease can cause significant swelling in the fingers and toes, creating a sausage-like appearance, called dactylitis.¹

Psoriatic arthritis in fingers and toes

Dactylitis is a painful swelling of the entire digit and is often asymmetric, occurring only on one side of the body. For example, all the joints in one finger on the left hand may be affected while the same finger on the right hand is unaffected. However, PsA can also be symmetrical, with joints affected on both sides of the body.² Studies show that dactylitis occurs more frequently in the toes than the fingers, with 78% of patients experiencing the swelling in the toes and 42% experiencing swelling in the fingers.¹

Dactylitis is a combination of swelling in the joint, as well as inflammation at the attachment points of ligaments and tendons. This type of inflammation is called enthesitis.¹ Dactylitis occurs in up to 50% of patients with PsA and is a marker for disease progression.² Dactylitis is a hallmark feature of PsA, although it occasionally occurs in other conditions, such as spondyloarthropathies, gout, or some infections.¹

Dactylitis can be acute or chronic. Acute dactylitis is defined by the painful swelling of the digit. Chronic dactylitis is characterized by persistent swelling with an absence of pain. Tender inflammatory dactylitis is associated with disease that erodes the joints, often leading to deformity and loss of function.¹

Progression

PsA is a chronic disease that can fluctuate and change over time. Some patients present with asymmetrical disease affecting only a few joints (oligoarthritis) at diagnosis and evolve to having symmetrical disease affecting many joints (polyarthritis). Others find that with effective treatment, the disease might go from polyarticular to oligoarticular.¹

Arthritis mutilans, the most severe form of the disease, occurs in approximately 5% of patients with PsA. The shortening of digits, deformity, and loss of function characterize arthritis mutilans.¹

How is psoriatic arthritis in the fingers and toes diagnosed?

PsA is often diagnosed with the use of imaging techniques, including x-ray, MRI (magnetic resonance imaging), and ultrasound. Ultrasound and MRI have been shown to be more sensitive than x-ray to detect inflammatory changes in patients with PsA. Ultrasound is useful for assessing structural changes and detecting abnormal blood flow. MRI allows visualization of soft tissue as well as bony changes.^1,3

How is psoriatic arthritis in the fingers and toes treated?

Minor pain and stiffness of mild PsA can be alleviated with non-steroidal anti-inflammatory drugs (NSAIDs). In addition, injections of corticosteroids may be used.⁴

For moderate to severe disease, treatments that target joint disease in PsA can reduce symptoms and prevent disease progression. Recommended treatments include disease-modifying anti-rheumatic drugs (known as DMARDs). The first step for treatments is usually DMARDs such as methotrexate, leflunomide, or sulfasalazine. Other treatments include medicines that target tumor necrosis factor (TNF), a chemical that produces a wide range of inflammation in PsA. Examples of TNF blockers include etanercept (Enbrel), adalimumab (Humira), infliximab (Remicade), golimumab (Simponi), and certolizumab pegol (Cimzia). Other DMARDs that have proven effective in clinical trials include ustekinumab (Stelara), brodalumab (which is awaiting FDA approval), and secukinumab (Cosentyx). ¹ The FDA has also recently approved Inflectra (infliximab-dyyb), a biosimilar to infliximab, for the treatment of PsA.⁶

Physical therapy and surgery

Physical and occupational therapy, involving exercises, stretching, heat, cold, and possible vocational readjustments, can be critical treatment approaches to protect the involved joints and maintain function.^4,5

Patients may be referred for possible surgery to alleviate severe pain or damage. However, high rates of recurrent joint damage have been noted after surgery for PsA, particularly in the hand.⁵