Collagen disease is a term that refers to disorders involving collagen, a type of protein found in many forms of connective tissue. Collagen is very tough and has a glue-like consistency. It makes up around 30% of the protein found in the body and is an important component of the body's physical structure. Diseases involving the collagen can lead to a variety of health problems.
Historically, this term was used to refer to connective tissue diseases, also known as systemic autoimmune diseases. People sometimes referred to such conditions as “collagen vascular diseases.” This usage of the term is considered outdated but still appears in some old textbooks and medical charts. Some examples of systemic autoimmune diseases include rheumatoid arthritis, systemic lupus erythematosus, scleroderma, and dermatomyositis.
In true collagen disease, the collagen itself is involved in the disease process. Collagen can become inflamed and this may lead to breakdowns of connective tissue that cause problems like joint pain, soreness, tenderness, and muscle weakness. This commonly occurs because the immune system mistakenly identifies collagen as an invader and begins to attack it. The collagen breaks down in response and the body may have difficulty replacing damaged collagen.
Some collagen defects are genetic. Certain congenital conditions can interfere with the ability to produce collagen. Many people with genetic connective tissue disorders do not produce enough collagen, cannot produce the right kinds of collagen, or overproduce collagen. A congenital collagen disease can lead to problems with the connective tissue that may lead to a variety of issues from organ damage to undersized or weak muscles.
A collagen disease can also be acquired. Certain types of infections have been linked with damage to the collagen, including diseases that can act as triggers to cause autoimmune disorders, where the body begins attacking itself. People can also develop collagen disorders as a result of repeated injuries, cancers, responses to medications, and other events.
When a doctor suspects that a patient has a collagen disease, biopsies may be requested so that connective tissue from the area of involvement can be examined under a microscope. A complete medical history will be conducted and a physical examination will be performed. This information will be used to develop a diagnosis so the doctor can discuss treatment or management of the disease. For some conditions, no cures are available, and treatment is focused on managing symptoms, keeping patients comfortable, and monitoring patients for signs of complications.