Nail psoriasis: a questionnaire-based survey.

BACKGROUND: Skin manifestations are the most characteristic finding of psoriasis. However, nail involvement is also a clinical feature of disease although it is often overlooked. The documented prevalence of nail psoriasis varies between 10·0% and 81·1%.
OBJECTIVES: The aim of this investigation is to gain knowledge about the prevalence and clinical manifestations of nail psoriasis and patient experiences of treatment of nail psoriasis.
METHODS: A structured, self-administered questionnaire was distributed to all members (n = 5400) of the Dutch Psoriasis Association. The questionnaire enquired about sociodemographic patient characteristics, disease-related data and treatment of nail psoriasis. Patients reported their nail manifestations with photographs after instruction. Patients with nail psoriasis were compared with patients without nail psoriasis.
RESULTS: A response rate of 27% was achieved. The prevalence of nail psoriasis was 66·0%. The most frequently observed psoriatic nail manifestation was pitting (65·4%), whereas red spots in the lunula were infrequently seen (6·5%). Patients with nail psoriasis more frequently stated psoriasis capitis (75·8% vs. 65·7%), genital psoriasis (32·7% vs. 20·3%) and psoriatic arthritis (46·4% vs. 30·6%) compared with patients with psoriasis without nail involvement. Only 16·0% of patients received treatment for nail psoriasis. Systemic therapies were most frequently stated as being effective for nail lesions.
CONCLUSIONS: Nail manifestations seem to be more prevalent in patients with psoriasis than previously thought. In addition, nail psoriasis is shown to be associated with widespread and more severe forms of psoriasis, and different treatment options are experienced as being effective for nail psoriasis. Notwithstanding, nail psoriasis is still an often overlooked feature of the disease.