A Study of Efficacy of Zinc Oxide Nanoparticles Coated Socks in Prevention of Unpleasant Foot Odor

Introduction Pitted keratolysis is a common skin disease, caused by various gram-positive bacteria including Corynebacterium species, Kytococcus sedentarius, Dermatophilus congolensis and Actinomyces species. These bacteria create small tunnels in the stratum corneum, causing pitted lesions at plantar areas. This condition is frequent accompanied by feet malodor and is commonly found in young male adults, especially in soldiers, miners and athletes. The reported prevalence of pitted keratolysis among naval cadets in Thailand was 38.7%. Predisposing factors related to pitted keratolysis are pedal hyperhidrosis and prolonged feet occlusion. Although this condition is generally not painful, our previous study in 2018 revealed adversely affects patients' quality of life.

Regarding treatment modalities of pitted keratolysis, various medications and life-style modification have been recommended. Previous studies revealed efficacy of topical choices, including benzoyl peroxide gel, clindamycin-benzoyl peroxide gel, glycopyrrolate cream, erythromycin gel, clindamycin solution, chlorhexidine scrub4 and mupirocin ointment. Oral antibiotics and botulinum toxin injection were also beneficial in pitted keratolysis. As to life-style modification, wearing cotton socks and opened footwear, and proper hygiene, have also been suggested.

Previous studies demonstrated efficacy of zinc oxide in broad-spectrum antibacterial properties. Thus, zinc oxide has been used in various medical and apparel industrial products. Moreover, Commander Choopong Chailark invented socks coated with zinc oxide nanoparticles and reported antibacterial property of those socks.

Objective The present study aimed to study the efficacy of zinc oxide nanoparticles coated socks in prevention of unpleasant foot odor

Material and Methods First-year naval rating cadets, who had no pedal malodor were invited to enroll in this study. Consent was informed and obtained from all participants. Participants were assessed for behavioral risk factors and level of foot odor measured by a self-assessed visual analogue scale (VAS), using questionnaires. Subjects were randomly assigned either zinc oxide nanoparticles coated socks or ordinary socks.During the study, using of other topical treatment such as topical antibiotics, antiperspirant or aluminum chloride was not allowed. Participants were advised to wear those socks every day and regularly washed thier socks. All were able to regularly participate in physical military training during the study. Two weeks after the study clinical examinations by dermatologists and the cadets' self-assessment questionnaires, including feet odor by using VAS, treatment satisfaction and adverse effects, were used to evaluate the effectiveness. Pitted lesions improvement at plantar areas, evaluated by dermatologists, was divided into no improvement, slight improvement (decrease of pitted lesions at feet for 1 level) and much improvement (decrease of pitted lesions at feet for at least 2 level). Data were analyzed using Predictive Analytics SoftWare Statistics version 18 (SPSS, Inc., Chicago, Illinois, USA).

Duration of study: 4 months

Study design: Randomized control trial

Inclusion criteria

• First-year naval rating cadets, who had no pedal malodor

Exclusion criteria

• The cadets who previously received any topical treatment including topical antibiotic, antiperspirant or aluminum chloride within 6 months prior to the study.