CREST causes thickening and tightening of the skin with deposition of calcific nodules.
Raynaud's phenomenon
is frequently the first manifestation of CREST/lcSSc, preceding other symptoms by years. Stress and cold temperature induce an exaggerated vasoconstriction of the small arteries, arterioles, and thermoregulatory vessels of the skin of the digits. Clinically this manifests as a white-blue-red transition in skin color. Underlying this transition is pallor and cyanosis of the digits, followed by a reactive hyperemia as they rewarm. When extreme and frequent, this phenomenon can lead to digital ulcerations, gangrene, or amputation. Ulceration can predispose to chronic infections of the involved site.
Esophageal dysmotility
Presents as a sensation of food getting stuck in the mid- or lower esophagus, atypical chest pain, or cough. People often state they must drink liquids to swallow solid food. This motility problem results from atrophy of the gastrointestinal tract wall smooth muscle. This change may occur with or without pathologic evidence of significant tissue fibrosis.
Sclerodactyly
Though it is the most easily recognizable manifestation, it is not prominent in all patients. Thickening generally only involves the skin of the fingers distal to the metacarpophalangeal joints in CREST. Early in the course of the disease, the skin may appear edematous and inflamed. Eventually, dermal fibroblasts overproduce extracellular matrix leading to increased tissue collagen deposition in the skin. Collagen cross-linking then causes a progressive skin tightening. Digital ischemic ulcers commonly form on the distal fingers in 30-50% of patients.
Telangiectasias
Marked telangiectasias occur on the skin of the face, the palmar surface of the hands, and the mucous membranes. Telangiectasias tend to be more numerous in people with other scleroderma related vascular disease. The number of telangiectasias and the sites involved tend to increase over time.
Other
Other symptoms of CREST syndrome can be exhaustion, weakness, difficulties with breathing, pain in hands and feet, dizziness and badly healing wounds. Patients with lcSSc commonly induce pulmonary artery hypertension which may result in cor pulmonale.
Cause
Crest syndrome involves the production of autoimmune anti-nuclear and anti-centromere antibodies, though their cause is not currently understood. There is no known infectious cause.
Diagnosis
CREST is not easily diagnosed as it closely mimics symptoms of other connective tissue and autoimmune diseases. Diagnoses are usually given when a patient presents two or more of the five major clinical symptoms. Additionally, blood exams can be given to test for a positive ANAs and ACAs or skin biopsies can be given to help confirm a diagnosis.
