Understanding Sarcoidosis – by Guest Writer, Megan Thomas

Wednesday 6th December 2023

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Sarcoidosis is a chronic inflammatory condition occurring primarily in the lungs and affecting approximately 1 in 10,000 people in the UK. Early symptoms include enlarged lymph nodes, flare-ups of skin pain, shortness of breath, tiredness and arrhythmia. The exact cause of sarcoidosis remains uncertain.

Sarcoidosis is a chronic inflammatory condition caused by the clustering of white blood cells (granulomas) — primarily in the lungs, skin, heart and lymphatic system. It is estimated that 1 in 10,000 people in the UK are affected, with 90% of cases suffering from pulmonary (lung) sarcoidosis. There is a greater reported incidence in women, with the 30-40-year age group a key demographic.

Early symptoms of sarcoidosis manifest as enlarged lymph nodes and flare-ups of pain on the skin. Patients may also experience shortness of breath, tiredness and arrhythmia. The exact cause of sarcoidosis remains uncertain. However, the disease progression is amplified by genetic and environmental factors associated with autoimmunity — the process in which the immune system attacks the body’s own cells. History of infection, allergies, genetics, smoking and other irritants place patients at greater risk of sarcoidosis.

Most symptoms of sarcoidosis can be reduced by simple treatments, including non-steroidal anti-inflammatory drugs like ibuprofen, and making healthier lifestyle choices. Sarcoidosis may also resolve on its own. However, the persistence of granulomas at organ sites such as the lungs, heart and central nervous system can be life-threatening due to increased tissue scarring, impeding vital processes in the body.

Glucocorticoids are the first line of treatment for severe cases of sarcoidosis. Immunosuppressive drugs used to treat other autoimmune conditions such as rheumatoid arthritis have also been used in cases where glucocorticoids have been ineffective. These include infliximab and disease-modifying antirheumatic drugs (DMARDs) like methotrexate. Although a high percentage of patients respond well to these treatments, tolerability issues can arise. Patients require regular monitoring to ensure they are on the safest course of treatment, highlighting the requirement for more effective, personalised patient treatment plans.

Other DMARDs and targeted therapies such as JAK and TNF inhibitors are currently under clinical investigation for the treatment of sarcoidosis. These treatments differ from others used to treat sarcoidosis as they target specific components and aid to block key signalling pathways of the autoimmune response. The results from clinical trials so far are promising and report partial or complete improvement of sarcoidosis in >50% of cases. Other treatments under clinical investigation include antigen-targeting (CLEAR trial), granuloma formation interference, and vitamin D supplementation.

With potential new treatments on the horizon, this is an exciting moment in sarcoidosis research. Current research into treatments will help elucidate the pathogenesis of sarcoidosis and should lead to improved treatment guidelines to advance disease management.