The prevalence of onychomycosis in psoriatic patients: a systematic review

Abstract

We systematically reviewed all available literature concerning the prevalence of onychomycosis in patients with nail psoriasis and the distribution of pathogens causing onychomycosis in this specific group of patients. Databases searched were Pubmed, EMBASE and the Cochrane Controlled Clinical Trial Register. All studies reporting on the prevalence of onychomycosis in nail psoriasis were obtained, and quality assessment was determined by the STrengthening the Reporting of OBservational studies in Epidemiology checklist. Literature search revealed 720 studies, of which 10 studies met the inclusion criteria. The major limitation of the review was the heterogeneity of the included studies, which prevented the possibility to conduct a meta analysis. However, the average prevalence of 18.0% of onychomycosis in psoriatic patients seems to be increased when compared with control groups and literature on healthy population, even though the ultimate evidence remains lacking. As in the literature hypothesized shift in causative agents from dermatophytes to yeasts and/or moulds could not be confirmed. The clinical consequence of the relatively high prevalence of onychomycosis in psoriasis may be a general advice to rule out onychomycosis or concomitant onychomycosis in these patients with (suspected) nail psoriasis. This advice is stressed by the relative simplicity of treating the contribution of onychomycosis in the nail dystrophy but also the fact that nail psoriasis mostly is treated by immunosuppressive drugs, like steroids, methotrexate or biologics which may aggravate mycotic nail infections.

Prevalence of onychomycosis among patients with nail psoriasis who are not receiving immunosuppressive agents: Results of a pilot study

“…Based on our results, the most plausible scenario explaining the high recorded frequency of onychomycosis among nail psoriasis patients seems to be the increased susceptibility of their nails to colonisation by pathogens, such as yeast and moulds, which tend to invade non‐healthy nails . These types of fungi rely on the altered structure and defective defence mechanisms of psoriatic nails to cause infection . Bigger observational studies, preferably cohort studies, will be able to further elucidate the two diseases’ relationship as well as establish causality.…”

Onychomycosis in patients with nail psoriasis: a point to point discussion

“…In addition to that, when the studies were examined individually, only three of them could conclude that their patients with nail psoriasis have a significant higher possibility to develop onychomycosis compared to healthy controls. The remaining seven studies found no significant differences, although many of them showed a trend to a higher prevalence of onychomycosis in patients affected by psoriasis with nail involvement …”

“…Recently, Klaassen et al . reviewed all the available literature concerning the prevalence of onychomycosis in patients with and without nail psoriasis. Only 10 studies met the inclusion criteria.…”

The development of a critical appraisal tool for use in systematic reviews addressing questions of prevalence

“…The group identified that the major area where prevalence reviews were disparate was in their conduct of critical appraisal or quality assessment of included studies. For example, whilst some reviews used instruments that were appropriate for reviews of prevalence data (9,10), others used instruments or criteria not designed to critically appraise studies reporting prevalence (such as reporting guidelines, study design specific tools, or self-developed criteria for their review question) (11)(12)(13), or refrained from conducting a formal quality assessment altogether (14,15). Therefore, the working group sought to address this gap by developing and testing a critical appraisal form that could be used for studies included in systematic reviews of prevalence data.…”