Other connective tissue diseases

Other connective tissue diseases

Rheumatoid arthritis

Most patients with rheumatoid arthritis have no skin disease, but some have tiny fingertip infarcts, purpura, ulcers, palmar or peri-ungual erythema, or pyoderma gangrenosum. The most common skin manifestations are marble-like nodules near joints.

These are always associated with the presence of rheumatoid factor. Some patients with rheumatoid arthritis have a vasculitis of larger blood vessels with deep ‘punched out’ ulcers on the legs.

Reiter’s syndrome

Reiter’s syndrome, precipitated by non-specific ure-thritis or dysentery, combines skin lesions, arthropathy, conjunctivitis, balanitis, mucositis and spondylitis. Arthritis is the most severe element. The skin lesions (keratoderma blenorrhagicum) are psoriasis-like red scaling plaques, often studded with vesicles and pus-tules, seen most often on the feet. The toes are red and swollen, and the nails thicken. Psoriasiform plaques may also occur on the penis and scrotum, with redness near the penile meatus. Topical steroids and systemic NSAIDs help, but many patients need methotrexate  and/or systemic steroids.

Relapsing polychondritis

This process can affect any cartilage as the disorder is apparently caused by autoimmunity to collagen. The ears are the usual target. The overlying skin becomes red, swollen and tender. The cartilage in joints, the nose and the tracheo-bronchial tree may be involved, so that patients develop floppy ears, a saddle nose, hoarseness, stridor and respiratory insuf-ficiency. Aortic aneurysms are also seen. Treatment is with systemic steroids and NSAIDs. Tracheostomy may be necessary.

Behçet’s syndrome

Behçet’s syndrome is discussed already.

Polyarteritis nodosa

This is discussed in earily but is considered by some to be a connective tissue disorder.

Panniculitis

Panniculitis is an inflammation of the subcutaneous fat. It includes a number of diseases with different causes but a similar appearance: some are listed in Table 10.6.

Presentation

Most patients have tender ill-defined red nodules on the lower legs, thighs and buttocks.

Course

This depends upon the cause. Migratory throm-bophlebitis may be associated with underlying malignancy. In lupus profundus, a panniculitis is associated with discoid or SLE. Erythema induratum may be caused by tuberculosis. Erythema nodosum leprosum is a reactional state in leprosy. Patients with pancreatitis may liberate enough lipase into the systemic circulation to cause fat in the skin to liquefy and discharge through the overlying skin. The Weber–Christian variant is associated with fever, but its cause is unknown. 

Investigations

The type of panniculitis can sometimes be identified by skin biopsy, which must include subcutaneous fat. A complete blood count, ESR, chest X-ray, serum lipase, serum α₁-antitrypsin and tests for antinuclear antibodies are needed.

Treatment

This depends upon the cause. Rest, elevation of affected extremities and local heat often help symptoms. NSAIDs may also bring help in the absence of specific therapy