interphalangeal joints of the fingers) and there can be associated tenosynovitis, but there is no erosion or deformation in the long term. Diarrhea may also occur. Mechanism
Immune complexes are thought to cause blood vessel damage, attracting neutrophils into the skin and synovium in BADAS. These antigen-antibody complexes are thought to be caused by excessive exposure to bacterial antigens (especially peptidoglycans). Bacterial overgrowth appears to be a frequent underlying condition. These antibodies possibly stimulate migration of neutrophils into the affected joints and skin. The effect of antibacterial therapy supports a role for bacteria in the disease mechanism (pathogenesis). Diagnosis
A diagnosis of this syndrome is made when an individual has the constellation of the characteristic recurrent neutrophilic dermatosis, flu-like symptoms, arthralgias or arthritis, and myalgias in the setting of a pathology of the bowels that is not best explained by another diagnosis. See also
Sweets syndrome-like dermatosis
List of cutaneous conditions


== References ==
An overlap syndrome is a medical condition which shares features of at least two more widely recognised disorders. Examples of overlap syndromes can be found in many medical specialties such as overlapping connective tissue disorders in rheumatology, and overlapping genetic disorders in cardiology. Rheumatology
Examples of overlap syndromes in rheumatology include mixed connective tissue disease and scleromyositis. Diagnosis depends on which diseases the patient shows symptoms and has positive antibodies for in their lab serology. In overlap syndrome, features of the following diseases are found (most common listed):
Systemic lupus erythematosus (SLE)
Systemic sclerosis
Polymyositis
Dermatomyositis
Rheumatoid arthritis (RA)
Sjögrens syndrome
Eosinophilic granulomatosis with polyangiitis (EGPA)
Autoimmune thyroiditis
Antiphospholipid antibody syndromeThe treatment of overlapping connective tissue disorders is mainly based on the use of corticosteroids and immunosuppressants. Biologic drugs, i.e. anti-TNFα or anti-CD20 monoclonal antibodies, have been recently introduced as alternative treatments in refractory cases. There are some concerns with the use of anti-TNF agents in patients with systemic autoimmune diseases due to the risk of triggering disease exacerbations.The term polyangiitis overlap syndrome refers to a systemic vasculitis that shares features with two or more distinct vasculitis syndromes. The most common type of polyangiitis overlap syndrome is microscopic polyangiitis (MPA), which shares features with EGPA, granulomatosis with polyangiitis and panarteritis nodosa. Sometimes polyangiitis overlap syndrome is used as a synonym for MPA. Gastroenterology
In gastroenterology, the term overlap syndrome may be used to describe autoimmune liver diseases that combine characteristic features of autoimmune hepatitis, primary biliary cirrhosis and primary sclerosing cholangitis.