Psoriasis patients frequently have nail involvement. It can significantly impact health-related quality of life (HRQoL) in addition to the impairments caused by other psoriasis symptoms, such as patients’ embarrassment over apparent nail abnormalities or functional impairment in manual activities and walking. It is particularly critical in nail psoriasis clinical trials to examine whether the therapy improves HRQoL deficits that are unique to nail psoriasis. There are two validated patient surveys available for this purpose: the Nail Psoriasis Quality of Life Scale (NPQ10) and the Nail Assessment in Psoriasis and Psoriatic Arthritis–Quality of Life Scale (NAPPA-QOL). The 10-item NPQ10 has the benefit of being brief and hence easy to administer. In contrast, the 20-item NAPPA-QOL measures the many components of HRQoL, which is a multidimensional entity. Despite this, the majority of randomised controlled studies on nail psoriasis do not assess HRQoL improvement. If they do, a variety of devices, the most of which are not nail-specific, are employed. This makes it impossible to compare trial results. 

Harmonizing HRQoL assessment in future clinical trials on nail psoriasis might increase study comparability and the reliability of meta-analyses.