Just like rheumatoid arthritis, collagenoses are among the inflammatory rheumatic diseases in which the immune system produces antibodies against the body’s own components. In this case, the connective tissue is the target of the attack by the autoantibodies, which trigger chronic inflammation there.
What are collagenoses?
Collagenoses are a group of rare autoimmune diseases in which the immune system perceives parts of the body’s connective tissue (the collagen) as foreign and forms antibodies against them. Since connective tissue is found in many organs, collagenoses often affect many organs simultaneously, such as mucous membranes or skin, lungs, heart or vessels. The diseases are usually chronic and can be very debilitating for the affected person. Women are much more likely than men to develop collagenosis, and the diseases usually occur in middle age.
What are the collagenoses?
The most common collagenosis is Sjögren’s syndrome, which affects about 500,000 people in Germany. Rarer are:
- The scleroderma
- The systemic lupus erythematosus
- The polymyositis/dermatomyositis
- The antiphospholipid syndrome and
- The mixed collagenosis, which is also called Sharp syndrome
In related diseases, there are also CREST syndrome, eosinophilic fasciitis (is also called Shulman syndrome) and diseases that have an external trigger and have a clinical picture similar to scleroderma. A few years ago in Spain, contaminated cooking oil was the trigger for many cases of this type of disease – some people died.
How do you recognize collagenosis?
Diagnosing collagenosis is a difficult matter. The clinical picture varies widely, and while antibodies to various cell components may be found in the laboratory, they do not necessarily appear. There are a number of diagnostic criteria for each collagenosis, called the ARA or ACR criteria, established by the American College of Rheumatology. Of these criteria, a certain number must be met for the diagnosis to be considered confirmed.
Sjögren’s syndrome
Sjögren’s syndrome is characterized by dry eyes, a dry mouth, and swelling of the parotid glands. The decrease in lacrimation can be objectified with a specific test called the Schirmer test. Decreased salivary secretion is checked by sialography and scintigraphy. An increase in various autoantibodies (against various cell nuclear components) and rheumatoid factor are also possible. Tissue sampling of the lower lip reveals increased inflammatory cells.
Scleroderma
Scleroderma causes hardening (sclerosis) of the connective tissue of a wide variety of organs. On the facial skin, this hardening leads to mimic rigidity and reduction of the mouth opening. Pigmentary changes and necrosis occur on fingers and toes, and peripheral blood flow is severely restricted in cold weather, resulting in severe pain (the technical term is Raynaud’s symptomatology). In the lungs, heart and kidneys, sclerosis leads to increasing functional impairment, which affects life expectancy. All joints become restricted in their mobility due to inflammation and hardening.
Other forms of collagenosis
In lupus erythematosus, symptoms range from joint pain, kidney inflammation, and skin symptoms – which gave this collagenosis its name – to increased sensitivity to light, Raynaud’s syndrome, and neuropsychiatric abnormalities such as seizures or psychosis, as well as possible blood level changes. Again, autoantibodies may be detectable, but need not be. Polymyositis mainly affects the muscles and the surrounding connective tissue. As soon as additional skin symptoms occur, the collagenosis is called dermatomyositis. In addition to severe muscle soreness, joints, lungs and heart may also be affected. The diagnosis is confirmed with a muscle biopsy and determination of muscle excitability. In antiphospholipid syndrome, the autoantibodies impair blood clotting. Thrombosis usually occurs, but there may also be an increased tendency to bleed. In young women who suffer multiple miscarriages, this collagenosis must be ruled out by differential diagnosis.Mixed collagenosis presents a collection of the most diverse symptoms of all collagenoses; fortunately, the prognosis is good.
