Clinical study on the effects of the applied volume of moisturizer in patients with asteatosis

Asteatosis is characterized by decreased stratum corneum water content, and the basic treatment is to keep the skin moisturized. Poor application of moisturizers by patients may reduce treatment efficiency, so it is important to continue application as instructed by dermatologists. Application instructions based on the finger‐tip unit are useful for patients, but there is no clear evidence of its efficacy. We investigated the effects of the volume of the moisturizer (Hirudoid(®) Cream 0.3%) administrated with 1/3 finger‐tip unit and 1 finger‐tip unit equivalent doses per target lower leg of patients with asteatosis (twice daily, 28 days) on the overall dry skin scores, itch numerical rating scale scores, and skin physiological parameters (stratum corneum water content, transepidermal water loss, and skin pH). Sixty patients were randomized with a 1:1 allocation ratio into two groups: the 1/3 finger‐tip unit and 1 finger‐tip unit equivalent dose groups. The results showed that 43.3% of the patients in the 1 finger‐tip unit equivalent dose group, compared with 13.3% in the 1/3 finger‐tip unit equivalent dose group, presented zero overall dry skin scores 1 week later. As the overall dry skin scores improved, the stratum corneum water content also increased. In patients with moderate itching, the itch numerical rating scale scores of the 1 finger‐tip unit equivalent dose group decreased significantly compared with those of the 1/3 finger‐tip unit equivalent dose group. The results suggested that the application of 1 finger‐tip unit equivalent dose of the moisturizer twice daily in clinical practice could induce remission more quickly. With the 1/3 finger‐tip unit equivalent dose, prolonged treatment may be necessary to achieve the desired effect; therefore, application adherence is strictly required. In conclusion, the application of a 1 finger‐tip unit equivalent dose would be quite reasonable in clinical practice.