Case history

A 65 year old woman developed a lump on the tip of her right ring finger that became painful, ulcerated, and discharged a white material (figure).

Questions

1. What is the abnormality on the hand x rays?
2. What are the two most likely causes of the white material discharging from the finger?
3. What is the underlying diagnosis?
4. What other manifestations of this conditions might affect this patient's hands?

Answers

1. The x rays show calcinosis.
2. The white discharge is most likely to be calcific deposits. It may also be pus if the finger has become infected.
3. Limited cutaneous scleroderma (or CREST syndrome).
4. Raynaud's phenomenon; ischaemia and gangrene of the fingers; skin oedema, thickening, tightening, and ulceration; joint contractures; nail fold capillary dilation and dropout; and telangectasia

Discussion

Scleroderma

Scleroderma is a multisystem disease characterised by thickening and tightening of the skin and narrowing of the arteries of the peripheries. Limited cutaneous scleroderma is a subset of systemic sclerosis. It is called this because the skin changes occur primarily in the hands and face. This distinguishes it from diffuse cutaneous scleroderma which involves the skin of the trunk and has a higher incidence of renal and lung complications.

CREST stands for calcinosis, Raynaud's phenomenon, "eosophageal" dysmotility (American spelling), sclerodactyly, and telangectasia as these conditions are prominent. The CREST syndrome has less early systemic complications and was thought to have a better prognosis than the diffuse cutaneous form of scleroderma. We now know, however, that there is a high incidence of pulmonary hypertension, usually occurring at least 10 years after diagnosis.

Raynaud's phenomenon

Raynaud's phenomenon is the most common presentation of scleroderma. Typical attacks are characterised by well demarcated blanching of the fingers. As the fingers recover their blood supply, they become blue and finally red. As the scleroderma progresses, the attacks are more intense and the gradual reduction in blood flow to the peripheries leads to ischaemia, cyanosis, poor healing, and sometimes
gangrene. Management of Raynaud's
phenomenon includes lifestyle measures (such as avoiding the cold and not smoking) and medication--usually calcium
channel blockers and topical nitrates. In severe cases--such as gangrene)--intravenous prostacyclin may improve digital blood supply.

In the early stages of scleroderma the hands may become oedematous. Later the swelling is replaced by thickening and the skin appears tight and shiny with loss of the normal skin creases. This appearance in the fingers is referred to as sclerodactyly or acrosclerosis. The skin may become so tight that flexion contractures develop in the finger joints. Topical emollients help with symptoms of itch and dryness. Regular stretching of the hands may minimise joint contractures.

In a patient who presents with Raynaud's phenomenon, it may be difficult to distinguish between early scleroderma and uncomplicated primary Raynaud's disease, if the skin thickening has not yet developed. In scleroderma, and some other connective tissue diseases, the capillaries of the nail beds are affected. Some capillaries become dilated while others become occluded. These appearances can be seen with an ophthalmoscope and are an indication that a connective tissue disease is present.

Calcinosis

Calcinosis refers to calcium hydroxyapatite deposits that form in the soft tissues of the fingers in patients who have CREST syndrome. They appear as hard nodules under the skin and may grow large enough to become painful or affect hand function. If the skin is thin they become visible as white or yellow chalky deposits, and if the skin breaks down calcific deposits are extruded. Secondary bacterial infection may occur and is suspected when there is an increase in pain, erythema, or an accumulation or discharge of pus. Swabs should be taken and the infection treated with sterile dressings, antibiotics, and sometimes debridement.