Perianal disease takes many forms, is very common and can impair quality of life significantly. The symptoms of perianal disease, including pain, bleeding, discharge and pruritus, are common to several conditions that are sometimes difficult to disentangle. It is crucial to identify the serious causes of perianal symptoms, but also to reduce the burden of the less dangerous conditions that nevertheless can be debilitating and interfere with an individual’s work, social or intimate life. Below we discuss some of the frequent and important mistakes made in the management of perianal disease based, where possible, on evidence, and where not, on clinical experience.

Familial Mediterranean fever (FMF), also called periodic disease, Armenian disease, etc., is a prototypical autoinflammatory disorder where the underlying mechanism is the dysfunction of innate immunity, resulting in unprovoked episodes of inflammation.¹ Although considered rare worldwide, it is prevalent in people of Mediterranean origin; however, one can expect to encounter patients in all parts of the modern world. FMF is a monogenic disease with autosomal recessive inheritance.² Unlike other monogenic disorders, the diagnosis remains largely clinical, and it is important to understand the limitations of genetic testing. Another distinguishing feature is the well-established effectiveness of lifelong monotherapy with colchicine in preventing attacks and complications.³

Coeliac disease is an autoimmune disorder triggered by gluten, which activates an immune reaction against the autoantigen tissue transglutaminase (TG2) in genetically predisposed subjects. Genetic susceptibility to coeliac disease has been proven by its close linkage with major histocompatibility complex (MHC) class II human leukocyte antigen (HLA) DQ2 and DQ8 haplotypes. The identification of biomarkers for coeliac disease (e.g. endomysial antibodies [EmA] and antibodies to TG2 [anti-TG2]) has changed the epidemiology of coeliac disease from being a rare to a frequent condition, with an expected prevalence of 1% in the worldwide population. Coeliac disease can be difficult to diagnose because symptoms vary from patient to patient, and the majority of patients who have coeliac disease remain undiagnosed. Small intestinal biopsy remains the gold standard for coeliac disease diagnosis, and a delayed diagnosis in the elderly can be considered a risk factor for complications. Complicated coeliac disease is not so frequent, but for those who have it, the prognosis is very poor, with a low rate of survival after 5 years.