Psoriatic arthritis (PsA) can involve the feet, from the heels to the toes. The effects can range from minor swelling and discomfort to debilitating damage that may become permanent. Flares of PsA symptoms can be managed, and a number of strategies can prevent problems.
PsA is a type of inflammatory arthritis that causes pain, swelling, and inflammation of the joints. It is an autoimmune disease that occurs due to immune system dysfunction that attacks healthy tissues.
Up to 85% of people with a history of psoriasis experience PsA, although you do not have to have psoriasis to have PsA.1
PsA targets joints and skin throughout your body, including the hands and feet. When it affects the feet, it might cause substantial pain and swelling, starting at the heels and going as far as the ends of your toes.
Foot involvement in PsA can lead to disability. Treatment for PsA and for specific foot symptoms can help you to feel better, manage your pain, slow down disease progression, reduce the frequency of flare-ups, and prevent joint damage.
Heels and Ankles
Enthesitis is a symptom unique to PsA and other types of spondylarthritis (types of arthritis that affect the spine). Enthesitis can help your doctor distinguish PsA from other types of inflammatory arthritis, like rheumatoid arthritis (RA).2
Enthesitis is pain and inflammation in the enthesis, the connective tissues between the bones and adjacent tendons or ligaments.
Inflammation of the enthesis can affect the heels and the ankles. In the heels, this inflammation occurs at the Achilles tendon—the tough band of tissue in the back of the foot. The Achilles tendon connects your heel bone to your calf muscle.
At the ankles, enthesis causes inflammation in the area where the tendons or ligaments meet bone to facilitate joint movement.
Pain and stiffness due to enthesis might be worse in the morning upon waking or after sitting for a long period.
Enthesitis of Achilles Tendon
One study reported in 2017 in the journal Arthritis & Care found that up to 35% of people with PsA develop enthesitis, with the Achilles tendon being the most commonly affected area.3 Inflammation at the Achilles tendon will cause pain and swelling at the heel, making it hard to walk, run, or climb steps.
As enthesitis worsens, your tendons and ligaments will become thicker, harder, and more swollen, which adds pain and difficulty when you step down on your foot. Your doctor can request an ultrasound or MRI to determine the extent of the enthesitis.
There is no specific treatment for enthesitis, and treatment is generally aimed at the cause. With PsA, that entails a mix of medication, rest, and physical therapy. Your doctor might recommend or prescribe:
Non-steroidal anti-inflammatory drugs (NSAIDs), including ibuprofen and naproxen, to manage the pain and reduce inflammation.
Corticosteroid therapy to reduce inflammation.4
DIsease-modifying anti-rheumatic drug (DMARD) or a biologic drug to slow down the effects of the disease.
Treatment with TNF inhibitors (biologics) is also sometimes recommended for the treatment of PsA associated enthesitis.4 Research shows that TNF therapies, like adalimumab, etanercept, infliximab, and golimumab, are quite effective for treating enthesitis. Adalimumab and etanercept have been reported to be effective for treating heel enthesitis, with continuing improvements lasting over six months.4
When enthesitis affects the Achilles tendon, it makes it harder for you to extend your ankle, which further adds to difficulties with walking. Swelling from the Achilles tendon can also extend into the back of the ankle, leading to ankle pain and problems with movement of the ankle.
Joint pain in the ankles with PsA is treated similarly to other types of inflammatory arthritis. This includes medication to relieve pain and prevent long-term damage. Treatment might also include lifestyle changes, bracing of the affected ankle, and anti-inflammatory medicines to ease inflammation, pain, stiffness, and swelling.
The midfoot is the middle part of the foot, containing a cluster of small bones that form an arch at the top of your foot. PsA affects the midfoot by causing generalized swelling throughout the midfoot, tenosynovitis, plantar fasciitis, and palmoplantar pustular disease.
Tenosynovitis is inflammation of the tendon sheath. It commonly affects the feet and ankles in people with PsA and it can also affect the foot flexor tendons. It leads to joint pain, swelling, and stiffness.
The flexor tendons help you to bend your toes and fingers. The flexor tendons that help you to bend your toes actually originate from two muscles of the lower leg.5 They run down to the inside of the ankle and under the foot.
A 2011 review in the Journal of Immunology Research looked at the results of one study that found tenosynovitis in the flexor tendons of the fingers and toes of people with PsA.6 In that study, ultrasound imaging showed thickness and swelling of the flexor tendons specific to PsA.
Plantar fasciitis causes inflammation in the plantar fascia. The plantar fascia is the dense band of connective tissue at the bottom of the foot that connects the heel to the front of the foot.
Some evidence suggests people with PsA might have a higher risk for plantar fasciitis.7 This is because enthesitis from PsA occurs commonly at the Achilles tendon, which attaches to the plantar fascia.
Plantar fasciitis can cause dull or sharp pain when you step down on your foot. Other symptoms include swelling and stiffness at the heel. Plantar fascia pain is treated with ice, rest, exercises, splinting and bracing, and taping (to relieve pressure off the plantar fascia).8
Both plantar fasciitis and palmoplantar psoriasis can affect the bottom of the foot at the sole and the plantar fascia.
People with PsA who have severe psoriasis are more likely to have a condition called pustular psoriasis, also called palmoplantar psoriasis (PPP).9
PPP causes blister-like sores on the soles of the feet, cracked skin, and red, scaly patches.10 These symptoms make walking painful and uncomfortable. PPP can also affect the palms of the hands.
Some researchers have suggested that PPP is a variant of psoriasis, while others believe it is a separate condition.10 The symptoms are caused by the immune system attacking healthy skin cells.
There is no cure for PPP, but it is treatable. PPP is treated with topical steroids and photochemotherapy, an ultraviolet radiation treatment.10 Other treatments include immunosuppressive drugs like cyclosporine.
The symptoms can be relieved permanently, but, in some instances, even with ongoing treatment, blisters and sores will keep coming back.9
PsA and the Toes
PsA can cause inflammation in the toes. Similar to the way PsA affects the fingers, it can cause swelling of one or more toes and changes to the toenails.
Dactylitis, sometimes called sausage toes, is a condition that causes swelling of entire digits (toes and fingers). It is often called sausage toes because the swollen toes resemble little sausages. One 2018 review of studies in the journal Seminars in Arthritis and Rheumatism finds up to 49% of people with PsA will have dactylitis.11
Dactylitis occurs when the small joints of the toe, as well as the entheses of the tendons, become inflamed. It is a very painful symptom of PsA that will affect your ability to walk, step down on affected toes, and wear socks or shoes comfortably.
Gout—another type of inflammatory arthritis—can also cause swelling and pain in your toes. Studies show people with PsA and/or psoriasis have a greater risk of developing gout.12
Gout is characterized by sudden, severe attacks of pain, swelling, tenderness, and redness of the joints, usually at the top of the toe. Gout symptoms will come and go, and there are ways to manage symptoms and prevent flare-ups. You can have symptoms of both gout and dactylitis at the same time.13
Metatarsophalangeal Joint Pain
The metatarsophalangeal (MTP) joints are located between your toes and the bones in the main part of the foot. PsA can cause pain in the areas of the toes where the MTP joints are located.14 MTP joint pain is caused by PsA inflammation and can lead to joint damage throughout the foot.
Synovitis is inflammation of the lining of the joints (the synovium), and it can affect the fingers and toes. Long-term synovitis in PsA might lead to bone destruction. This is especially common when inflammation starts at the entheses and then triggers secondary joint synovitis.11
Distal Interphalangeal Predominant PsA
Distal interphalangeal predominant (DIP) PsA primarily affects the small joints of the fingers and toes that are closest to the finger and toenails. It affects about 10% of people with PsA.6
DIP PsA causes stiffness and pain in the toes, especially in the morning. Stiff and painful toes make to harder to walk and stand for long periods. DIP PsA may also cause nail changes, including detachment, discoloration, crumbling, and pitting (small indents).
Arthritis mutilans is a severe and rare effect of PsA. It affects less than 5% of people with PsA.15 It causes severe inflammation that eventually causes damage to the feet and toes, shortening of toes, deformity, and loss of use. Early and thorough treatment can reduce the effects of this complication and should start as soon as AM is diagnosed.
What You Need to Know About Arthritis Mutilans
Up to 80% of people with PsA will have nail involvement, according to a 2017 report in the journal Reumatologia.16 Nail symptoms of PsA are visible and include pitting, white spots, discoloration, onycholysis (nails separating from the nail bed), and onychorrhexis (brittle nails).
Additional nail symptoms may include hyperkeratosis (buildup of grey keratin cells under the nails) and splinter hemorrhages (tiny blood spots under nails from damaged capillaries in the nail beds). Fungal nail infections are also common with PsA.16
Nail Problems Associated with Psoriasis
Treatment of PsA with DMARDs and/or biologics can help to improve symptoms of dactylitis and enthesitis and reduce or prevent the inflammation that's responsible for other foot and toe symptoms.15
Treatment that specifically focuses on PsA of the feet and toes will depend on how severe your symptoms are and might include steroid injections directly into a joint or beneath a toenail.17
And because foot and toe involvement might indicate severe systemic disease, your doctor will likely revisit your PsA treatment plan to determine if a different treatment regimen might help get the disease under control.
Your doctor might also recommend some things for you to do at home to manage symptoms, such as:
Using cold packs to reduce pain and bring down swelling
Keeping your nails short to reduce nailbed separation
Wearing shoes that offer support and give your feet room to breathe
Elevating your feet to get pressure off and ease swelling
Soaking your feet in warm water. Ask your doctor if it is safe for you to use Epsom salt.
Taking anti-inflammatory pain relievers to bring down swelling and ease pain
How Psoriatic Arthritis Is Treated
Prevention of Foot and Toe Involvement
PSA is a chronic condition that requires ongoing treatment. While there is no cure for the condition, there is a lot you can do to manage symptoms, control inflammation, protect your joints, and reduce the effects it can have on your feet and toes.
To keep your feet healthy, make sure you stick to your treatment plan. Your doctor might prescribe medications to relieve pain and inflammation or to slow down disease progression. Your doctor may also recommend that you maintain a healthy weight to reduce stress on the joints of your feet, relieve foot pain, and improve your gait (the way you walk).
Exercise is important to keep joints flexible and boost your energy. Try activities that put the least amount of stress on your joints, such as swimming and walking. Focus on stretching the joints, ligaments, and tendons that are the source of foot pain. Ask your treating doctor or physical therapist about exercises that are safe for your feet.
A Word From Verywell
If PsA has affected your feet, make sure your doctor knows about any foot problems you are experiencing. This includes nail changes, pain, and morning stiffness. Getting the right diagnosis and treatment for your feet as early as possible is the best way to improve your quality of life and to keep you moving.