Our publication on sarcoidosis, a multisystem inflammatory disease, the aetiology of which has still to be resolved, is published today [1]. From the outset sarcoidosis has been considered an unusual condition; many patients are unaware they have the disease with the majority recovering spontaneously and without treatment. For a smaller, but significant, proportion of patients like my own mother-in-law, there can be devastating and, on occasions, fatal consequences. Despite agreement that the condition is influenced by a variety of genetic and environmental interactions, many questions remain unanswered. These questions, with no specific ‘cure’, or biomarker of disease presence, means sarcoidosis has frequently been designated an ‘enigma’.

The proposed mechanism is that individuals with a susceptible genotype are exposed to one or more potential antigens. A sustained inflammatory response follows, which ultimately results in pathognomonic granuloma formation. Various clinical phenotypes exist with specific genetic associations influencing disease susceptibility, protection, and clinical progression.

Occupational and environmental factors, including microbial elements, may then effect the development of this disease. Sarcoidosis is a heterogeneous disease, showing geographic and racial variation in clinical presentation. It demonstrates a familial tendency and clear genotype associations. In addition, it appears to cluster within closely associated populations (e.g., work colleagues) and appears to be related to selected occupations and environmental exposures.

Frequently occult, but occasionally fatal, this disease has a very variable prognosis. It is also unusual (even now) in having no specific biomarker. The epidemiology and multiple factors that appear to influence the aetiology of sarcoidosis illustrate why this disease state is frequently described as a clinical enigma. In our manuscript we review comprehensively the available literature on the disease.

References

1. Dubrey S, et al. Sarcoidosis: the links between epidemiology and aetiology. Postgrad Med J. 2014 Oct;90(1068):582-9.