This site is intended for healthcare professionals as a useful source of information on the diagnosis, treatment and support of patients with lupus and related connective tissue diseases.

Introduction

Foot problems in lupus patients can involve any of the tissue structures within the foot (Table 1). Joint problems can lead to hallux valgus, forefoot spread and clawed or hammered toes. A high incidence of bunions and calluses has been found with these deformities along with associated pain and tenderness. Foot deformities may not be regularly reported since they are hidden and are possibly less disabling when compared to hand or finger deformities and cannot always be attributed to lupus since they are also widespread in the general population. Serious joint deformity is rare, however, over 80% of patients with Jaccoud’s arthropathy of the hands have been described as having ‘lupus foot’ with similar abnormalities to those found in the hands, i.e. paratendonitis, synovitis, deformity and subluxation in the toes and metatarsophalangeal joints (MPJs).

It is important to note that lupus foot problems may be compounded by the dermatological complications of lupus. Neurological and circulatory problems such as Raynaud’s phenomenon and vasculitis are common with possibly serious consequences such as digital gangrene. Steroid therapy further increases the risk of infection and peripheral ulceration and so any lupus patient should warrant ‘high risk’ podiatry care.

Table 1 - Foot problems in LUPUS

Vasculitis
Peripheral vascular disease
CNS & Peripheral neuropathy
Raynaud’s phenomenon
Chilblains
Hypersensitivity
Arthritis
Jaccoud’s arthropathy
Osteonecrosis
Tendonitis
Myositis
Nail dystrophy
Nailfold problems
Hyperkeratosis

The range of podiatric problems

Two thirds of lupus patients have one or more radiographic abnormalities in their feet, mainly subluxation (37%), diffuse osteopenia (29%) or cystic changes (20%). Joint involvement is usually symmetrical often presenting in the knees, ankles, MPJs or proximal interphalangeal joints (IPJs). There is usually tenderness and sometimes swelling although there is often a lack of objective signs of inflammation. Synovitis with effusions is common and deformity is often of the reducible type found with Jaccoud’s athropathy although osteophytic lipping and calcification of digital joint capsules have been seen. Repeated synovitis may cause a deviation and subluxation of the MPJs, with resulting plantar pressure lesions, similar to the pattern found in rheumatoid arthritis. Foot problems tend to be worse in patients with severe hand problems and the severity increases with time.

Musculo-skeletal problems include painful tenosynovitis and tendonitis. Tendon rupture, particularly in weight bearing areas, has been reported -– usually as complication of local or systemic corticosteroids. Plantar fasciitis is common and in some cases may even be a prodrome of lupus. Hypersensitivity of minor skin and nail lesions is frequently found. Peripheral neuropathies may occur from transverse myelitis and mononeuritis multiplex due to arteritis possibly causing major loss of foot function, although this is very rare. Myalgia has been seen as a result of myositis in 50% of lupus patients and gait problems can arise from muscle atrophy and weakness around the pelvis and upper leg.

Around 25% of patients have nail changes, often onycholysis or complete loss of the nails, growth may be slow and atrophic with pitting. Periungual erythema with telangiectasia can lead to skin atrophy around the nail and thickening of the nail plate with transverse and longitudinal ridges – often associated with acute phases of disease or with Raynaud’s phenomenon. It has been suggested that the pattern of nail capillaries might demonstrate an evolution from undifferentiated to a specific collagen disease.The lupus patient often has tortuous, meandering capillaries with a prominent subpapillary plexus. Callus formation in the nail sulcus (onychophosis) is a common complaint but seems especially painful in lupus and can lead to infarcts and ulceration. Onychophosis can lead to an ingrown toenail as the patient tries to cut down the side of the nail, in an attempt to relieve the pain, causing a spike or wedge of nail to become embedded in the nail sulcus leading to further complications such as infected hypergranulation tissue.

Corns and callus due to mechanical stress on dysfunctional feet, with joint subluxations and toe deformities, form a large proportion of the work in routine podiatry clinics, however, the pain reported by lupus patients is often disproportionate to clinical observations and experience from non-lupus patients. Hyperkeratotic papules have been described as ‘exquisitely tender’ and lesions vary from inflamed weeping lesions to anhidrotic fissures.The pain can be severe and difficult to reduce with analgesics. Thrombocytopenia may cause haemorrhagic bullae and transient bullae may have caseous discharges. Purpura, discoid plaques, and erythematous macules or papules may be present and, unusually, massive hyperkeratosis with an underlying caseous layer has been described. Atrophy of the epidermis, degeneration of the dermal-epidermal junction, dermal oedema with inflammatory infiltrate and fibrinoid degeneration of the connective tissue have also been found.

Vascular complications may cause the most concern in the lower limb (Table 2), although major ischaemic problems are rare. Chilblains are common and it has been suggested that DLE patients with persistent chilblains may be at risk of developing systemic lupus. The reported incidence of Raynaud’s phenomenon varies but is probably about 15-20% although it has been reported to precede lupus in a significant number of cases. This digital vasospasm may have an inflamed, cyanotic or ischaemic presentation and is frequently associated with chilblains but can lead to gangrene and amputation if not treated soon enough. The risk of digital necrosis is further increased in patients with APS due to hypercoagulation. Thrombophlebitis has been found in 10% of patients and deep vein thrombosis can also be a recurrent problem. Vasculitis, when it occurs, commonly affects small blood vessels, arterioles and post-capillary venules, forming papular, erythematous and purpuric lesions. This may also lead to splinter haemorrhages and small tender infarcts, particularly around the nail fold and in the lower leg. Slowly healing ulcers may form over areas prone to pressure or trauma such as the malleoli. Macrovascular occlusive disease has been reported in a very few cases leading to gangrene and lower limb amputation or arterial bypass.

Table 2 - Possible Lower Limb Vascular Problems

Teliangectatic lesions
Dermal Vasculitis
Thrombophlebitis
Raynaud’s phenomenon
Livido Reticularis
Chronic Ulcers
Peripheral Gangrene
Dermal infarcts (similar to those in Degos Disease or Atrophe Blanch)

Treatment of the Lupus Foot

The key aims in the treatment of the feet of any high risk patient must be prevention of serious complications, reducing pain and increasing mobility. The risk of ulceration will be increased several times if impaired circulation co-exists with foot deformities. Orthopaedic and neurological problems will lead to gait abnormalities, shoe fitting problems and increased pressure on the feet. Increased sensitivity will cause more pain whilst decreased sensitivity may reduce the patient’s awareness of potential problems. Increased ground reaction forces and decreased ability to accommodate these result in more dermal stress, corns, calluses and the risk of ulceration due to decreased circulation and tissue viability. Regular assessment of the feet is essential, with advice to the patient about daily hygiene, inspection and footwear. There is no need to cause alarm if the lower limb is not affected by the disease but if risk factors become apparent podiatric referral becomes essential.

Treatment may involve aseptic reduction of corns and calluses with padding or strapping to decrease stress on the affected area or even splinting to stop motion in the toes or feet. Advice on footwear or the possible provision of insoles or surgical shoes may be needed. Biomechanical control is important and orthoses may be prescribed to stabilise the foot as a result of muscle imbalance or deformity. This may prevent or reduce compensation and wear on other joints and possible traumatic vasculitis leading to necrosis. Correct nail care is also vital and periungual problems often need skilful and sensitive treatment. Partial nail avulsion may be an option where there is co-existing nail involution or cryptosis but this may be contra-indicated by poor tissue viability leaving conservative methods of nail and hypertrophied skin reduction with nail-sulcus packing as the options of choice combined with footwear and home-care advice.

Podiatric surgery

If surgery becomes necessary, considerations should primarily involve the degree of deformity and level of pain rather than the ongoing inflammatory process. Special consideration should be given to the presence of other potentially complicating factors caused by lupus, medication etc.

Despite the relative risks, lupus patients usually respond well to carefully planned, timed and supported interventions for foot deformity. Surgery can provide great benefit and pain relief when deformity is causing a high level of morbidity in an otherwise active patient.

Podiatric Referral

The treatment of podiatric problems needs to be wide ranging and will frequently call for a multi-disciplinary approach with professionals such as wound care nurses, physiotherapists and orthotists, monitored by a specialist in connective tissue disease. More serious problems can be avoided by early examination, preventative treatment and advice. This has already been found to be cost effective and to reduce morbidity and amputation with other disease processes such as diabetes.There is some disparity between podiatry departments in those patients accepted for treatment and the service provided, however, it is common practice to see ‘at risk’ patients, particularly as a result of impaired circulation.

Table 3 - Risk Factors Affecting the Lupus Foot

Arthropathy and deformity
Neuropathy
Haematological disease
Vascular disease
Oedema
Cortico-steroid and other drug therapy
Stephen Miller
Podiatry Manager
Dudley PCT & Matthew Boulton College
of Further & Higher Education Birmingham
Mrs Helen Williams
Consultant in Podiatric Surgery
The Foot Centre
West Midlands Hospital