CREST syndrome is one expression of a larger disease known as systemic sclerosis (or, if you’re stuck in your ways like me, “scleroderema”). But that’s the old name and we should try to use the more widely applicable “systemic sclerosis.” Ok, I’ll try.

Systemic sclerosis is an autoimmune disease in which patients accumulate excessive fibrosis throughout the body, most commonly in the skin of the hands and face, but also in the viscera. In advanced cases, hands can become claw-shaped, and the patient’s face may take on a mask-like appearance.

The etiology is somewhat obscure (as is frustratingly common in most autoimmune diseases). It does appear that CD4+ (helper) T cells accumulate for some reason, releasing cytokines that do all kinds of bad stuff, like activate mast cells and macrophages, which release fibrogenic cytokines.

Microvascular damage plays a big role in this disease. The arteries of the hands, for example, show intimal proliferation in nearly 100% of patients. For some (again, unknown) reason, endothelial cells are damaged, and platelets aggregate, both of which lead to the laying down of fibrotic tissue in and around vessels. That makes it pretty hard for the blood to get through small vessels, and tissue downstream shows ischemic injury and scarring.

Systemic sclerosis has been divided into two types: diffuse and limited.

In diffuse systemic sclerosis, patients experience widespread skin involvement at the onset of the disease. There is rapid progression and early visceral involvement (particularly in the lungs, kidneys, and heart). This subtype is more common, unfortunately. The prognosis is worse than it is for the limited type; overal 10-year survival is between 35 and 70% (a wide spread!).

In limited systemic sclerosis, patients often have skin involvement that is confined to the fingers, forearms and face. Visceral involvement in this type occurs late. The clinical course is pretty benign; the disease may exist for decades without progressing much.

Now here’s where the CREST syndrome comes in (finally!). Some patients with limited SS develop a combination of several features:

• Calcinosis
• Raynaud phenomenon (as seen in the image above)
• Esophageal dysmotility
• Sclerodactyly
• Telangiectasia

It’s easier to use the acronym CREST instead of listing all the features.