What is rheumatoid arthritis?
Rheumatoid arthritis (RA) is classified as a connective tissue disease. It is a chronic systemic inflammatory disorder that damages the joints of the body. Classic symptoms of rheumatoid arthritis include joint swelling, deformity, pain, weakness, and stiffness of the smaller joints such as those of the hands, wrists, elbows, knees, ankles and feet. These are referred to as the articular manifestations of the disease. When rheumatoid arthritis affects other organs of the body these are known as extra-articular manifestations.
Skin changes of rheumatoid arthritis are considered extra-articular manifestations and can be divided into two types: general cutaneous manifestations and specific cutaneous manifestations.
General cutaneous manifestations
Patients with rheumatoid arthritis may experience a wide array of non-specific skin changes. General signs and symptoms include:
- Skin becomes atrophic (thin and wrinkled), making it fragile and easy to bruise
- Skin on the back of the hands may become pale or even translucent
- Nails may become brittle and split length-wise
- The palms become reddened (palmar erythema)
Specific cutaneous manifestations
Many people with rheumatoid arthritis form subcutaneous nodules. These are lumps that appear on or near the affected joint and are visible just beneath the skin.
|Classic rheumatoid nodules|
|Rarer causes of rheumatoid nodules|
Neutrophils are a type of white blood cell (leucocyte). They are present in bacterial infections. They are the prominent cell seen on skin biopsy of some uncommon inflammatory skin diseases known as neutrophilic dermatoses.
Interstitial granulomatous dermatitis
Also known as ‘rheumatoid papules’, interstitial granulomatous dermatitis presents as skin coloured or red papules or plaques often on the trunk. Annular configuration is often noted. Interstitial granulomatous dermatitis is rare. The diagnosis is made when distinctive pathological features are seen on biopsy.
Cutaneous vasculitis may be a complication of rheumatoid arthritis and is characterised by dark purplish areas on the skin (purpura) caused by bleeding into the skin from blood vessels damaged by rheumatoid arthritis. Skin changes caused by rheumatoid vasculitis include:
- Skin ulcers (usually leg ulcers) may be extensive and painful
- Petechiae (purplish spots) or purpura
- Nail fold or edge breakdown (digital infarcts)
In addition to skin changes, rheumatoid vasculitis can cause many internal symptoms, including sensory or motor neuropathy (loss of sensation), hepatomegaly (enlarged liver), splenomegaly (enlarged spleen), bowel ulcers, and haematuria (blood in urine).
- Sayah A, English JC. Rheumatoid arthritis: a review of the cutaneous manifestations. J AM Acad Dermatol 2005;53:191-209
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