Potential Uses of Nonthermal Atmospheric Pressure Technology for Dermatologic Conditions in Children

Nonthermal atmospheric plasma (NTAP)(or cold atmospheric plasma [CAP]) is a rapidly developing treatment modality for a wide range of dermatologic conditions. Plasma (or ionized gas) refers to a state of matter composed of electrons, protons, and neutral atoms that generate reactive oxygen and nitrogen species.¹ Plasma previously was created using thermal energy, but recent advances have allowed the creation of plasma using atmospheric pressure and room temperature; thus, NTAP can be used without causing damage to living tissue through heat.¹ Plasma technology varies greatly, but it generally can be classified as either direct or indirect therapy; direct therapy uses the human body as an electrode, whereas indirect therapy creates plasma through the interaction between 2 electrode devices.^1,2 When used on the skin, important dose-dependent relationships have been observed, with CAP application longer than 2 minutes being associated with increased keratinocyte and fibroblast apoptosis.² Thus, CAP can cause diverse changes to the skin depending on application time and methodology. At adequate yet low concentrations, plasma can promote fibroblast proliferation and upregulate genes involved in collagen and transforming growth factor synthesis.¹ Additionally, the reactive oxygen and nitrogen species created by NTAP have been shown to inactivate microorganisms through the destruction of biofilms, lead to diminished immune cell infiltration and cytokine release in autoimmune dermatologic conditions, and exert antitumor properties through cellular DNA damage.^1-3 In dermatology, these properties can be harvested to promote wound healing at low doses and the treatment of proliferative skin conditions at high doses.¹

Because of its novelty, the safety profile of NTAP is still under investigation, but preliminary studies are promising and show no damage to the skin barrier when excessive plasma exposure is avoided.⁴ However, dose- and time-dependent damage to cells has been shown. As a result, the exact dose of plasma considered safe is highly variable depending on the vessel, technique, and user, and future clinical research is needed to guide this methodology.⁴ Additionally, CAP has been shown to cause little pain at the skin surface and may lead to decreased levels of pain in healing wound sites.⁵ Given this promising safety profile and minimal discomfort to patients, NTAP technology remains promising for use in pediatric dermatology, but there are limited data to characterize its potential use in this population. In this systematic review, we aimed to elucidate reported applications of NTAP for skin conditions in children and discuss the trajectory of this technology in the future of pediatric dermatology.

Methodology

A comprehensive literature review was conducted to identify studies evaluating NTAP technology in pediatric populations using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. A search of PubMed, Embase, and Web of Science articles was conducted in April 2023 using the terms nonthermal atmospheric plasma or cold atmospheric plasma. All English-language articles that described the use of NTAP as a treatment in pediatric populations or articles that described NTAP use in the treatment of common conditions in this patient group were included based on a review of the article titles and abstracts by 2 independent reviewers, followed by full-text review of relevant articles (M.G., C.L.). Any discrepancies in eligible articles were settled by a third independent researcher (M.V.). One hundred twenty studies were identified, and 95 were screened for inclusion; 9 studies met inclusion criteria and were summarized in this review.

Results

A total of 9 studies were included in this review: 3 describing the success of NTAP in pediatric populations^6-8 and 6 describing the potential success of NTAP for dermatologic conditions commonly seen in children (Table).^9-14

Studies Describing Success of NTAP—Three clinical reports described the efficacy of NTAP in pediatric dermatology. A case series from 2020 showed full clearance of warts in 100% of patients (n=5) with a 0% recurrence rate when NTAP treatment was applied for 2 minutes to each lesion during each treatment session with the electrode held 1 mm from the lesional surface.⁶ Each patient was followed up at 3 to 4 weeks, and treatment was repeated if lesions persisted. Patients reported no pain during the procedure, and no adverse effects were noted over the course of treatment.⁶ Second, a case report described full clearance of diaper dermatitis with no recurrence after 6 months following 6 treatments with NTAP in a 14-month-old girl.⁷ After treatment with econazole nitrate cream, oral antibiotics, and prednisone failed, CAP treatment was initiated. Each treatment lasted 15 minutes with 3-day time intervals between each of the 6 treatments. There were no adverse events or recurrence of rash at 6-month follow-up.⁷ A final case report described full clearance of molluscum contagiosum (MC), with no recurrence after 2 months following 4 treatments with NTAP in a 12-year-old boy.⁸ The patient had untreated MC on the face, neck, shoulder, and thighs. Lesions of the face were treated with CAP, while the other sites were treated with cantharidin using a 0.7% collodion-based solution. Four CAP treatments were performed at 1-month intervals, with CAP applied 1 mm from the lesional surfaces in a circular pattern for 2 minutes. At follow-up 2 months after the final treatment, the patient had no adverse effects and showed no pigmentary changes or scarring.⁸

Studies Describing the Potential Success of NTAP—Beyond these studies, limited research has been done on NTAP in pediatric populations. The Table summarizes 6 additional studies completed with promising treatment results for dermatologic conditions commonly seen in children: striae distensae, keloids, atopic dermatitis, psoriasis, inverse psoriasis, and acne vulgaris. Across all reports and studies, patients showed significant improvement in their dermatologic conditions following the use of NTAP technology with limited adverse effects reported (P<.05). Suwanchinda and Nararatwanchai⁹ studied the use of CAP for the treatment of striae distensae. They recruited 23 patients and treated half the body with CAP biweekly for 5 sessions; the other half was left untreated. At follow-up 30 days after the final treatment, striae distensae had improved for both patient and observer assessment scores.⁹ Another study performed by Suwanchinda and Nararatwanchai¹⁰ looked at the efficacy of CAP in treating keloids. They recruited 18 patients, and keloid scars were treated in halves—one half treated with CAP biweekly for 5 sessions and the other left untreated. At follow-up 30 days after the final treatment, keloids significantly improved in color, melanin, texture, and hemoglobin based on assessment by the Antera 3D imaging system (Miravex Limited)(P<.05).¹⁰

Kim et al¹¹ studied the efficacy of CAP for the treatment of atopic dermatitis in 22 patients. Each patient had mild to moderate atopic dermatitis that had not been treated with topical agents or antibiotics for at least 2 weeks prior to beginning the study. Additionally, only patients with symmetric lesions—meaning only patients with lesions on both sides of the anatomical extremities—were included. Each patient then received CAP on 1 symmetric lesion and placebo on the other. Cold atmospheric plasma treatment was done 5 mm away from the lesion, and each treatment lasted for 5 minutes. Treatments were done at weeks 0, 1, and 2, with follow-up 4 weeks after the final treatment. The clinical severity of disease was assessed at weeks 0, 1, 2, and 4. Results showed that at week 4, the mean (SD) modified Atopic Dermatitis Antecubital Severity score decreased from 33.73 (21.21) at week 0 to 13.12 (15.92). Additionally, the pruritic visual analog scale showed significant improvement with treatment vs baseline (P≤.0001).¹¹