What Is Dactylitis Psoriatic Arthritis?

"Dactylitis" is the clinical name for when your fingers and toes are swollen, tender, warm, and inflamed due to a psoriatic arthritis (PsA) flare-up or an associated condition. The name comes from the Greek word for finger ("dactylos"). 

With dactylitis, your fingers can become so swollen that they look like sausages, which is why this condition and characteristic symptom is sometimes referred to as "sausage fingers" or "sausage digits." Swelling in the toes can make it difficult to get around.

Signs and Symptoms of Dactylitis

Dactylitis in PsA, a chronic, inflammatory disease of the joints that can also cause a skin disorder called psoriasis, often occurs asymmetrically, meaning on just one side of the body. It involves the feet more than the hands, and it affects multiple digits (fingers or toes) at the same time.

Dactylitis is common in 16%–49% of people who experience psoriatic arthritis. It can be the first sign of the illness, and it may also be the only symptom for several months or years before other symptoms of PsA develop. 

Symptoms in affected fingers or toes include:

• Inflammation
• Swelling
• Redness
• Stretched or shiny appearance to the skin
• Pain
• Warmth

Causes

The underlying cause of dactylitis in PsA is an overactive autoimmune response, when your body mistakenly attacks healthy tissue. It results in inflammation in the finger or toe joints, making digits swell. When you have PsA, you can experience skin symptoms and joint pain on one or both sides of your body and psoriasis, scaly, itchy patches of skin, anywhere on your body. 

Genetics

Around 25% of patients with autoimmune diseases have a tendency to develop additional autoimmune disorders. Factors that may cause PsA or other autoimmune diseases include genetics and the environment.

Researchers say three genes in particular cause inflammatory illnesses. These genes are:

• HCK
• CD53
• TYROBOP

Dactylitis in PsA, in particular, is associated with specific gene expressions called human leukocyte antigen (HLA) B alleles that are part of your immune system. Specific HLAs that are established genetic markers for dactylitis in PsA include:

• HLA-B*27
• B*38
• B*39:01
• B*08

A specific gene signature associated with inflammatory diseases can be identified. It significantly overlaps with other gene structures associated with digestive disorders, cancers, and disorders affecting brain functioning (neurodegenerative disorders).

Associated Conditions

Besides PsA, you may have other underlying conditions that contribute to or cause dactylitis. Researchers have used ultrasound and magnetic resonance imaging (MRI) technologies to gain a deeper understanding of dactylitis, but the exact cause is still unknown. 

Conditions that may cause dactylitis other than psoriatic arthritis include:

• Blistering distal dactylitis is swelling on the other side of your thumb pad that can even extend down to the nail bed. It’s mainly caused by a streptococcal bacterial infection, the same type of bacteria that causes strep throat.
• Tenosynovitis is inflammation of the lining of a tendon's sheath. This sheath provides a layer between your joints. It is meant to reduce friction and increase ease of motion. This type of chronic inflammation can lead to scarring, which further limits joint movement.
• Joint synovitis is basically the same as tenosynovitis except the breakdown happens to the inner lining of the joint rather than the outer protective layer.
• Soft-tissue and bone marrow edema is a form of swelling caused by fluid being trapped in the tissues in the area. If you have soft tissue edema or bone marrow tissue, it becomes the root of the issue as opposed to arthritis in cases of psoriatic arthritis. 
• Enthesitis is inflammation in the spaces where your tendons and ligaments join with your bones.
• Erosive bone damage occurs when inflammation takes little bites out of the bone. Any form of damage to your bones will cause inflammation in the area, meaning it could be the cause of dactylitis.

Diagnosis

Your doctor will diagnose dactylitis based on a physical examination, X-rays or MRI (magnetic resonance imaging) scans, and your symptom history. You will also likely be tested for various biomarkers, or indicators, in your blood that can provide a better idea of current levels of inflammation or damage. These tests can also help narrow down treatment options and indicate whether you have other conditions that may be causing the swelling.

Some examples include blood tests and synovial fluid analyses (to test the thick liquid that lubricates joints) that can help your doctor rule out other types of arthritis, such as gout, rheumatoid arthritis (RA), or osteoarthritis (OA).

Treatment

If the cause of dactylitis is PsA, you will likely work with a rheumatologist (a specialist who diagnoses and treats diseases of the muscles, bones, joints, ligaments, and tendons) to determine the best course of treatment to help manage symptoms.

NSAIDs

NSAIDs (nonsteroidal anti-inflammatory drugs) are typically the first-line treatment for pain relief and reducing inflammation. These come in over-the-counter (OTC) and prescription strengths depending on pain severity.

OTC NSAIDs include Advil and Motrin (ibuprofen), Aleve, (naproxen), and aspirin. Side effects typically include upset stomach, dry mouth, and drowsiness. These medications can be dangerous if taken in high, frequent doses, potentially causing gastritis, ulcers, and kidney dysfunction.

Topical pain relievers

Ointments and creams are available to reduce pain and swelling in the fingers and to help with symptoms of psoriasis. The American Academy of Dermatology recommends products that contain calamine, camphor, hydrocortisone, or menthol. These ingredients tend to work best on itchy psoriasis.

OTC creams containing hydrocortisone 1% or prescription-strength 2.5% applied twice daily are said to be effective in many cases. Stronger options do exist, if needed.

Prescriptions

In addition to prescription-strength NSAIDs and hydrocortisone cream, you can ask your doctor or dermatologist about safe and effective options like:

• Disease-modifying anti-rheumatic drugs (DMARDs) like methotrexate are used to treat inflammatory conditions and slow the disease process by modifying the immune system.
• Glucocorticoid injections (steroid injections) can suppress inflammation and can relieve pain when injected into affected joints. Oral options aren't advised for PsA because they can cause severe psoriasis.
• Calcipotriene (cream, solution, ointment, or foam, or as a combination ointment, suspension, or foam with betamethasone dipropionate) is a form of topical vitamin D therapy for treating the symptoms of psoriasis. Vitamin D moisturizes, protects, and helps neutralize your skin to prevent flares.

Newer drugs are also available for psoriatic arthritis and include:

• Otezla (apremilast), a PDE4 inhibitor
• Cosentyx (secukinumab), an injectable monoclonal antibody that blocks interleukin 17
• Stelara (ustekinumab), an injectable monoclonal antibody that blocks interleukin 23

Coping

Coping with PsA can include making lifestyle changes, including those in the following list.

Product changes

Take an assessment of your current soaps, detergents, and lotions. Do they have skin-drying ingredients? Or, do they leave a filmy residue on your skin? Many skin care products can trigger psoriasis symptoms.

Use scent- and dye-free options to reduce irritation. Look for options with coal tar, an ingredient derived from coal that can help reduce psoriasis symptoms, including redness, swelling, and itching.

Reduce and manage stress

Any steps to reduce or manage your stress levels in general can also help delay PsA flare-ups. Stress contributes to inflammation and both of them create challenges to other activities that are necessary for general well-being like exercising, stretching, or socializing with others.

Reducing stress can include things like offloading some tasks from your proverbial plate or learning to get comfortable with "good enough."

Nutritional choices

If you have dactylitis from psoriatic arthritis or another condition, you may have already noticed how consuming certain foods and beverages can worsen symptoms. Certain ingredients, especially if consumed in excess, can make joint or skin inflammation symptoms worse. 

Foods that increase fluid retention include those with added salt and highly processed foods. It's important to monitor how your favorite foods affect your symptoms, including swelling, and act accordingly.

If your fingers or toes are swelling or flaring up, talk to your doctor. The causes of dactylitis are many and can range from factors out of your control (genetics) to those you can change (lifestyle modifications). It’s good to know why your body is creating this type of inflammation. Seeing a doctor will identify the cause of your dactylitis, which can help you find the right solutions, get the quickest relief possible, and keep future flare-ups at
bay.