What Autoimmune Diseases Cause Foot Pain?

At least a dozen autoimmune diseases can cause foot pain, and in some of them the foot is the very first place symptoms appear. Rheumatoid arthritis is the most recognized culprit, but psoriatic arthritis, lupus, Sjögren’s syndrome, systemic sclerosis, and several others can damage joints, tendons, nerves, and blood vessels in the feet. The type of foot pain, where it strikes, and what it feels like vary enough between conditions that the pattern itself sometimes points toward a diagnosis.

Rheumatoid Arthritis

Rheumatoid arthritis (RA) has a well-documented tendency to attack the forefoot. The small joints at the base of the toes, called metatarsophalangeal (MTP) joints, are frequent early targets. Over time, unchecked inflammation reshapes these joints, producing hallux valgus (a bunion) and claw-toe deformities that make walking painful with every step. Despite advances in drug treatment, forefoot deformity remains common enough that surgical resection of the metatarsal heads is still considered the standard procedure for disabling forefoot pain in RA patients.¹

The midfoot and hindfoot are vulnerable too. One lesser-known complication is rupture of the tibialis posterior tendon, the tendon that helps hold up the arch. When RA weakens it to the point of tearing, the arch collapses and the foot flattens, producing pain along the inner ankle and making it difficult to stand on tiptoe or walk on uneven ground.² This flat-foot deformity can be mistaken for simple aging or overuse if a clinician does not connect it to the underlying autoimmune process.

RA also weakens bone. Chronic inflammation and the corticosteroids used to control it both reduce bone density, making insufficiency-type stress fractures more likely. These are fractures that occur during normal daily activity rather than from a hard impact. In one documented case, a patient initially suspected of having osteoarthritis in the foot turned out to have multifocal stress fractures across the knee, ankle, and foot on MRI.³ If you have RA and develop sudden new foot pain without an obvious injury, stress fractures should be on the radar.

Psoriatic Arthritis and Spondyloarthritis

Psoriatic arthritis (PsA) produces a distinctive kind of foot involvement: dactylitis, the diffuse swelling of an entire toe that gives it a sausage-like appearance. Dactylitis is most strongly associated with PsA and the broader family of spondyloarthritis conditions, though it occasionally shows up in other inflammatory diseases.⁴ Unlike the symmetrical joint swelling in RA, a swollen sausage toe tends to be asymmetric and can appear before any skin plaques are visible, making it easy to misdiagnose.

Where PsA and other spondyloarthritides really distinguish themselves is enthesitis, inflammation at the points where tendons and ligaments anchor to bone. The Achilles tendon and the plantar fascia are two of the most commonly affected sites. In a study of patients with spondyloarthritis and clinical heel pain, MRI showed entheseal inflammation or structural damage at the Achilles tendon or plantar fascia in roughly 84% of cases.⁵ That means the pain you feel at the heel is usually backed by visible tissue changes, not just sensitivity. The distinction matters because enthesitis-driven heel pain responds to different treatments than the plantar fasciitis most people are familiar with.

PsA can also produce skin involvement on the soles of the feet. Palmoplantar pustulosis, a condition of recurring sterile pustules on the palms and soles, overlaps with PsA in roughly 10 to 25% of cases.⁶ The pustules themselves are painful, and the underlying joint inflammation adds a second layer of discomfort.

Reactive Arthritis

Reactive arthritis develops after certain bacterial infections, usually gastrointestinal or urogenital. It belongs to the spondyloarthritis family and shares many of the same foot-targeting features, including enthesitis and dactylitis. One distinguishing sign is keratoderma blennorrhagica, a pattern of crusty, psoriasis-like skin lesions on the soles of the feet that can be painful to walk on. In a reported case, a patient developed lower-limb arthritis along with inflammatory back pain, sausage-like toe swelling, and these sole-of-foot lesions, all following an infection.⁷ Reactive arthritis tends to be self-limiting over months, but the foot pain during active flares can be severe enough to prevent weight-bearing.

Systemic Lupus Erythematosus

Lupus affects the feet through several pathways at once. Joint inflammation can hit any joint in the foot, and unlike RA, lupus arthritis tends not to erode bone visibly on X-ray, which sometimes leads clinicians to underestimate how much pain the patient is in. Beyond the joints, lupus can damage blood vessels, cause Raynaud’s phenomenon in the toes, and produce skin lesions on the feet. A narrative review of lupus and foot involvement noted that the disease affects the lower limb through both musculoskeletal and vascular routes, but also pointed out a notable gap: there is surprisingly little published research specifically focused on how lupus affects the feet.⁸ That research gap means lupus foot problems may be underrecognized in practice.

Lupus patients are also at risk for avascular necrosis, a condition where bone tissue dies because of disrupted blood supply, and peripheral neuropathy from nerve inflammation. Both can contribute to foot pain that feels quite different from joint aches. Numbness, burning, or a sensation of walking on pebbles may indicate nerve involvement rather than joint inflammation.

Systemic Sclerosis

Systemic sclerosis (scleroderma) affects the feet in ways that are underappreciated. In a study of patients with the condition, about a quarter reported foot pain, and visible foot lesions were found in 35% of patients. Among those with foot lesions, almost all of them (about 94%) also experienced foot pain.⁹ The diffuse subtype of the disease, along with the presence of calcinosis (calcium deposits under the skin) and Raynaud’s phenomenon in the feet, were all linked to vascular foot lesions.

What makes systemic sclerosis distinctive is that the skin itself tightens and hardens. On the feet, this restricts movement of the toes and ankle, creates pressure points inside shoes, and makes the skin fragile and prone to ulcers. Digital ulcers on the toes from poor blood flow can be intensely painful and slow to heal. Calcinosis, where chalky calcium lumps form under the skin, tends to develop over bony prominences like the toes and heels, adding mechanical pain on top of the vascular damage.

Sjögren’s Syndrome and Autoimmune Neuropathies

Sjögren’s syndrome is mostly known for dry eyes and dry mouth, so foot pain catches many patients off guard. The mechanism here is nerve damage rather than joint inflammation. In a study of 20 consecutive patients with Sjögren’s-related neuropathy, 80% presented with burning feet as a symptom, and 60% had sensory symptoms that did not follow the typical “stocking” pattern you might expect with diabetic neuropathy.¹⁰ Skin biopsies in these patients confirmed reduced density of the tiny nerve fibers in the skin, which is what produces the burning and tingling sensations.¹¹

This type of nerve damage, called small-fiber neuropathy, is tricky to diagnose because standard nerve conduction studies often come back normal. The small unmyelinated fibers that carry pain and temperature signals are too fine for those tests to pick up. A skin punch biopsy, where a tiny sample of skin is examined under a microscope for nerve fiber density, is the more reliable way to confirm it. If you have Sjögren’s and your feet burn or tingle but your nerve tests look clean, that does not mean the symptoms are imaginary.

Other autoimmune conditions can damage nerves in the feet as well. Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), an autoimmune condition that attacks the insulating layer around nerves, produces pain in close to half of patients according to pooled estimates. About 14% of those with pain experienced it specifically in the distal extremities, meaning the feet and hands, while most had pain closer to the trunk.¹² In CIDP, weakness and numbness are usually more prominent than pain, but the combination can make walking unstable and exhausting.

Autoimmune Vasculitis

Vasculitis, inflammation of blood vessels, can affect the feet through two routes. The first is reduced blood flow, which can cause skin ulcers, discoloration, and aching pain in the toes. The second, more dramatic route is nerve damage from infarction of the small blood vessels that supply peripheral nerves. In two reported cases, patients developed foot drop, where the foot cannot be lifted at the ankle, as the earliest sign of primary systemic vasculitis. One had microscopic polyangiitis and the other had polyarteritis nodosa, and in both, the peroneal nerve was damaged by small-vessel inflammation before any other organ was obviously involved.¹³

Foot drop from vasculitis is sudden, not gradual. If your foot suddenly will not lift and there has been no injury, disc problem, or prolonged leg crossing to explain it, vasculitis belongs on the list of possibilities. The treatment is aggressive immunosuppression, and outcomes for the nerve damage depend heavily on how quickly it is recognized.

Foot Pain in Children With Autoimmune Arthritis

Juvenile idiopathic arthritis (JIA) is the most common chronic autoimmune joint disease in children, and the feet are hit hard. In one study of 144 children with JIA, all but nine had at least one identifiable foot problem. Pronation of the rearfoot and midfoot was found in roughly 73% and 72% of patients respectively, and about a third had splayfoot or restricted ankle motion.¹⁴ These are not minor findings. Pronation and alignment problems in a growing child change how forces travel through the leg, potentially affecting the knees and hips as well.

A survey of children with JIA found that about 63% reported some degree of foot impairment, and over half reported that their foot problems limited daily activities like running or playing.¹⁵ These limitations persisted even in children already receiving disease-modifying drugs and specialist foot care. The lower limb problems in JIA include not only joint swelling and pain, but also enthesopathies such as plantar fasciitis and Achilles tendinitis, muscle wasting, and in some cases limb-length differences if growth plates are affected.¹⁶

Children are less likely to articulate foot pain clearly, especially younger ones. A child who starts limping, avoids running, walks on the insides of their feet, or complains of “tired legs” may be dealing with foot-level inflammation. Early referral to a specialist who regularly examines children’s feet makes a meaningful difference in preventing long-term structural changes.

How Autoimmune Foot Pain Differs From Gout

Gout is worth mentioning because it is the single most common inflammatory arthritis, and it famously targets the foot, particularly the base of the big toe. However, gout is a crystal deposition disease, not an autoimmune process. It results from uric acid crystallizing in joints, and the foot is a preferred target partly because the extremities are cooler (crystals form more readily at lower temperatures) and because the mechanical stress of walking may seed crystal nucleation.¹⁷

The practical distinction matters because a sudden, agonizing flare at the big toe joint in someone without a known autoimmune disease is far more likely to be gout than RA. Gout attacks come on within hours, peak in a day or two, and resolve within a week or so without treatment. Autoimmune arthritis tends to build more gradually and persist. That said, the two can coexist, and psoriatic arthritis can mimic gout closely enough to require joint aspiration to tell them apart. If you have a hot, swollen big-toe joint for the first time, getting the fluid tested for crystals is the most reliable way to distinguish gout from autoimmune inflammation.

Imaging and Detection

Autoimmune foot pain is harder to pin down on imaging than many patients expect. Standard X-rays can miss early inflammation entirely, since they mainly show bone changes that take months or years to develop. In early RA, MRI and ultrasound are both more sensitive for detecting active inflammation in the foot. A study comparing the two found fair to good agreement between MRI findings of bone marrow edema and ultrasound findings of blood-flow changes in the joints, though the agreement varied by specific joint and was strongest in the outer toes.¹⁸

For enthesitis at the heel, MRI is considered the gold standard because it can visualize both soft tissue inflammation and early bone changes at the tendon insertion. Ultrasound is more accessible and can be done in a clinic visit, making it useful for monitoring over time. The key takeaway is that a normal X-ray does not rule out autoimmune inflammation in the foot. If your symptoms point toward an autoimmune cause and the X-ray is clean, pushing for ultrasound or MRI is reasonable.

Foot Surgery in Patients on Biologic Therapies

Many people with autoimmune diseases take biologic medications that suppress parts of the immune system. A common concern when foot surgery is needed, whether for joint correction, tendon repair, or other procedures, is whether these drugs increase the risk of infection or poor wound healing at the surgical site. A systematic review looking specifically at foot and ankle surgery in RA patients on biologics concluded that biologic use was not a risk factor for surgical site infection or delayed wound healing.¹⁹ That finding is reassuring, though decisions about whether to pause a biologic around surgery are still made on a case-by-case basis between rheumatologists and surgeons.

Orthotic devices, custom insoles, and supportive footwear remain first-line strategies across nearly all autoimmune conditions that affect the foot. Redistributing pressure away from inflamed joints, supporting a collapsing arch, or cushioning a heel with enthesitis can meaningfully reduce daily pain. These measures do not treat the underlying disease, but they buy time and comfort while systemic therapies work on the inflammation.