Relapsing polychondritis is a rare and systemic autoimmune disease. It is characterized by repeated episodes of inflammation in cartilage and other connective tissues. The condition is uncommon, with an estimated incidence of about 0.7 new cases per million people per year. This disorder arises when the immune system mistakenly attacks the body’s cartilage, leading to various health issues. The progressive nature of the inflammation can lead to permanent damage to the affected structures.
Affected Body Systems and Symptoms
One of the most common symptoms is auricular chondritis, a sudden, painful inflammation of the outer ear’s cartilage. This causes redness or a purplish discoloration and swelling, sparing the soft earlobes which lack cartilage. Repeated episodes can damage the cartilage, leading to a “cauliflower ear” or “floppy ear.”
Inflammation can also target cartilage in the nose, known as nasal chondritis. This causes pain, fullness, and sometimes a collapse of the nasal bridge. This collapse results in a “saddle nose” deformity, a visible change in the facial structure.
Joint involvement is another frequent symptom, presenting as inflammatory arthritis. This causes pain and swelling in various joints, from the hands to the knees. The arthritis is non-erosive, meaning it does not destroy joint bone, and can affect joints asymmetrically.
A serious development is inflammation of cartilage in the respiratory tract, including the larynx and trachea. Symptoms include hoarseness, a persistent cough, and tenderness over the larynx. Severe inflammation can cause a narrowing of the airway (tracheal stenosis), which obstructs breathing and can be life-threatening. The disease can also affect other systems, causing eye inflammation, skin rashes, and cardiovascular problems like inflammation of the aorta or heart valves.
The Diagnostic Process
Diagnosing relapsing polychondritis is a clinical process, as no single test can confirm the condition. Physicians rely on characteristic signs and symptoms, using established guidelines like the McAdam’s criteria. These guidelines require a patient to exhibit at least three of six specific clinical features, which include recurrent inflammation of both ear cartilages, non-erosive arthritis, and chondritis of the nasal or respiratory tract cartilage.
A biopsy of inflamed cartilage, often from the ear, can support a diagnosis. Under a microscope, the tissue sample may show changes consistent with the disease, like cartilage loss and inflammatory cell infiltration. This procedure helps to confirm the presence of chondritis and can aid in distinguishing it from other conditions with overlapping symptoms.
Blood tests are a standard part of the workup, though their results are not specific to this disease. Tests for inflammatory markers like ESR and CRP are often elevated, indicating systemic inflammation. Imaging studies like CT scans or MRIs can assess involvement in areas like the trachea, bronchi, or aorta, helping to identify airway narrowing or vascular complications. The process also involves ruling out other disorders like granulomatosis with polyangiitis or infections that can mimic its presentation.
Underlying Autoimmune Mechanisms
Relapsing polychondritis is an autoimmune disorder where the immune system mistakenly attacks its own healthy tissues. The primary target of this attack is cartilage. The immune system treats cartilage as a foreign invader, initiating an inflammatory response that leads to tissue damage.
The precise trigger for this autoimmune process is unknown. The mechanism is believed to involve an immune response targeting proteins abundant in cartilage. One implicated component is type II collagen, a protein that gives cartilage its structure. Evidence suggests the immune system may produce antibodies that attack this protein.
This attack involves a coordinated effort from various parts of the immune system. The resulting inflammation causes the pain, swelling, and redness seen during flares. Over time, chronic inflammation can destroy the cartilage, causing the functional and structural problems associated with the disease.
Treatment and Management Strategies
Treatment for relapsing polychondritis is tailored to disease severity and focuses on controlling inflammation and preventing long-term damage. For acute and severe flares, high-dose corticosteroids like prednisone are the primary treatment. These medications quickly suppress the immune system, reducing inflammation and alleviating symptoms.
For long-term management and to prevent flares, physicians prescribe disease-modifying antirheumatic drugs (DMARDs) or other immunosuppressants. Medications like methotrexate or azathioprine help modulate the immune system, which can reduce dependency on corticosteroids and their side effects. For cases that do not respond to conventional therapies, biologic drugs that target specific immune system components may be considered.
Managing this condition involves monitoring and addressing complications, particularly those affecting the airways. If laryngotracheal involvement leads to airway narrowing, medical interventions may be necessary. Procedures like placing a stent to hold the airway open or surgical reconstruction might be required to ensure proper breathing. Proactive management of complications is important for improving long-term outcomes.