Sarcoidosis and autoimmune diseases: differences, similarities and overlaps

Area of Science:

• Rheumatology
• Immunology
• Pulmonology

Background:

• Sarcoidosis is a rare multisystem granulomatous disease with unknown pathogenesis.
• It shares clinical features with autoimmune diseases but lacks specific autoantibodies or serologic markers for diagnosis.
• Sarcoidosis can mimic or coexist with connective tissue diseases and vasculitis.

Purpose of the Study:

• To review potential common etiologic factors between sarcoidosis and autoimmune diseases.
• To compare clinical, laboratory, and imaging features of sarcoidosis and autoimmune conditions.
• To highlight the diagnostic challenges and management considerations for overlapping diseases.

Main Methods:

• Systematic review of literature comparing sarcoidosis and autoimmune diseases.
• Analysis of clinical presentations, laboratory findings, and imaging characteristics.
• Evaluation of potential shared risk factors and etiological agents.

Main Results:

• Autoimmune diseases can precede or follow sarcoidosis diagnosis; prevalence of co-existence is largely unknown.
• Presence of autoantibodies in sarcoidosis warrants suspicion of an underlying or co-occurring autoimmune disease.
• Silica dust exposure is linked to increased prevalence of both sarcoidosis and rheumatoid arthritis.
• Autoimmune thyroid disease, Sjogren's syndrome, and ankylosing spondylitis are reported more frequently in sarcoidosis patients.

Conclusions:

• A thorough diagnostic work-up is essential for patients with sarcoidosis to identify overlapping autoimmune features.
• Clinicians must consider immune-modulating therapies, as they can lead to paradoxical reactions.
• Understanding shared etiologies and clinical presentations improves diagnosis and management of patients with co-existing sarcoidosis and autoimmune diseases.