Author(s): Iván Guerra [*] 1 , Javier P Gisbert 2
adalimumab; anti-TNF; Crohn's disease; inflammatory bowel disease; infliximab; psoriasis; ulcerative colitis
Inflammatory bowel disease (IBD) is a chronic inflammatory process that includes Crohn's disease (CD) and ulcerative colitis (UC). Although its etiology is unknown, immune mechanisms play an essential role in its chronic development and progression  . TNF-[alpha] is a cytokine with a critical role in the pathogenesis of several inflammatory diseases such as IBD or psoriasis  . Because of this, anti-TNF agents are among the therapeutic options available for IBD [3-5] . Currently, the anti-TNF agents infliximab (IFX), adalimumab (ADA) and certolizumab pegol have proven to be effective in inducing and maintaining remission in CD, with IFX also used to treat UC. ADA was approved in April 2012 for the treatment of UC in Europe. The use of anti-TNF drugs has led to a very significant advance in the treatment of IBD and other chronic inflammatory diseases such as psoriasis or psoriatic arthritis  .
Psoriasis is a cutaneous autoimmune disease characterized by hyperproliferation and abnormal differentiation of keratinocytes mediated by abnormal T-cell cytokine production  . The incidence of psoriasis is increased in IBD patients when compared with the general population, with an odds ratio of 1.8 having been described in patients with CD [8,9] . The use of anti-TNF drugs is approved for the treatment of moderate-to-severe psoriasis  .
The onset of psoriatic lesions has been observed paradoxically in patients on anti-TNF treatment due to diseases other than from psoriasis, including patients with IBD. This review aims to analyze the characteristics of reported cases with this phenomenon and to propose management recommendations based on our best current understanding.
The authors performed a systematic literature search using MedLine databases to identify any cases of anti-TNF induced psoriasis in IBD patients published until June 2012. Epidemiological data, characteristics of psoriasis and management after the development of skin lesions were recorded from each report. Statistical analysis includes a descriptive statistical analysis. Qualitative variables were expressed as percentages with CI, and quantitative variables were expressed as the mean and standard deviation or median and interquartile range, based on the presence or absence of a normal distribution.
A review of psoriasis induced by anti-TNF agents was published in 2011, including a report of 30 new cases  . It included a total of 156 patients reported until April 2011; six of them were excluded from the analysis because details on individual cases were not available  . Since this report, our group has published a series of 21 patients with psoriasis induced by anti-TNF agents  . The Mayo Clinic experience from 1998 to 2010 has been published, including 22 CD patients  . We contacted the authors of this study, who confirmed that none of the 22 aforementioned cases had been previously reported or published, although details on individual cases were not available. There have been 15 cases reported in nine publications that were not included in the previous reviews [15-23] . Until June 2012, 214 cases of psoriasis induced...