Melatonin and the Human Hair Follicle.

BACKGROUND: Melatonin, a pleiotropic hormone, affects the physiological processes including that of the hair follicle. We seek to identify the scientific evidence to support the potential benefits of melatonin in human hair growth. OBJECTIVE: To summarize the evidence on the association between melatonin and hair health, denoted by hair growth. METHODS: A literature review using 3 databases (PubMed, Google Scholar, and Cochrane) identified studies investigating the relationship between melatonin and hair loss (2022). The following search terms were used: (hair OR hair loss OR alopecia OR hair growth OR effluvium OR scalp) and (melatonin). Two independent reviewers screened studies for inclusion criteria, and data collection included demographics, melatonin intervention, study type, and effects on hair. RESULTS: A total of 11 human studies were identified with evidence of melatonin use in subjects with diagnosed alopecia (2,267 patients; 1,140M). Eight of the studies reviewed observed positive outcomes after topical melatonin use in subjects with androgenetic alopecia (AGA). Most studies report improved scalp hair growth (n=8), density (n=4), and hair shaft thickness (n=2) among melatonin users compared with controls. Effective topical melatonin dosage appears to be 0.0033% or 0.1% solution applied once-daily for 90 to 180 days vs 1.5 mg twice-daily oral melatonin supplementation for 180 days. CONCLUSION: There is evidence to support melatonin use to facilitate scalp hair growth, particularly in men with AGA. Further studies should include more patients and investigate the mechanism of action. J Drugs Dermatol. 2023;22(3): doi:10.36849/JDD.6921.

A case of eruptive lichen spinulosus after toxic epidermal necrolysis.

We report a case of a 13-year-old boy who presented with eruptive monomorphic white papules on the trunk and arms involving regions previously affected by toxic epidermal necrolysis (TEN). Biopsy revealed compact keratin involving the hair follicle and sparse mixed perivascular infiltrate, findings consistent with lichen spinulosus. Improvement was noted after treatment with ammonium lactate 12% lotion. While cutaneous dyschromia and xerosis are common after TEN, lichen spinulosus has not yet been described in the literature. It is important for providers to be aware of any potential cutaneous sequelae of TEN that can affect quality of life in order to best counsel their patients.

Erythromelalgia successfully treated with low-dose gabapentin in a pediatric patient.

Primary erythromelalgia, while uncommon, may significantly decrease the quality of life of those affected. While many patients with erythromelalgia require systemic therapy, there is no standard of care for this condition. Herein, we report a 7-year-old girl who experienced resolution of erythromelalgia symptoms with no adverse effects after treatment with low-dose gabapentin. We also discuss the safety and efficacy of low-dose gabapentin in children for treatment of pain.

Systemic Medications Associated With Hair Texture Changes.

BACKGROUND: In addition to hair loss, alterations in hair texture can be a worrisome side effect of certain medications yet are seldom reported and poorly characterized. OBJECTIVE: To systematically analyze the scientific literature to characterize medication-associated hair texture changes. METHODS: Relevant primary literature within PubMed and Cochrane was reviewed from 1985-2021 including 31 articles (1 randomized controlled trial with texture changes incidentally noted, 6 cohort, 1 cross-sectional, 23 case studies), comprising 2594 patients. RESULTS: Texture changes were associated primarily with antineoplastic agents (n = 97), antiepileptics (n = 56), retinoids (n = 15), immunomodulators (n = 3), and antiretroviral therapy (n = 1). Average age was 48.4 years old (41.2% female). De novo or exaggerated curling patterns were most commonly reported. Average time to texture change varied from 4.5 months (immunomodulators) to 17 months (antiretrovirals). Prognosis was seldom discussed with reversibility noted across all medication classes (n = 17/21; 3 weeks to 5 years post therapy). Irreversible changes were linked with antiretrovirals, retinoids, and antineoplastics. LIMITATIONS: Inability to define true incidence rates, ethnicity, and severity of texture changes due to the nature of available literature. CONCLUSIONS: Hair texture changes are potential side effects of antineoplastics, antiepileptics, retinoids, immunomodulators, and antiretroviral therapy. As these can have associated psychosocial impact, awareness among prescribing physicians is important.J Drugs Dermatol. 2022;21(9):989-996 doi:10.36849/JDD.6852.

Coconut, Castor, and Argan Oil for Hair in Skin of Color Patients: A Systematic Review.

Coconut, castor, and argan oils are popular commercial hair oils culturally rooted in current and historical Indian and African heritages. Dermatologists treating hair and scalp conditions often face challenging patient questions of whether over-the-counter hair oils should be used. This is particularly challenging given the deeply rooted cultural practices of some skin of color patients. As a result, many dermatologists recommend patients to continue using hair oils not based on clinical efficacy but rather lack of foreseeable side effects. We analyzed the literature to investigate claims to substantiate whether these hair oils can improve hair growth, hair quality, and treat infestation clinically. Based on 22 articles that met inclusion criteria, coconut oil has been shown to treat both brittle hair and hair infestation clinically, with limited evidence regarding its impact on hair growth. There is weaker evidence for castor oil improving hair quality by increasing hair luster, and no strong evidence supporting its use for hair growth or treatment of infestation. Argan oil does not have any significant evidence supporting its use to improve hair growth, quality, or treatment of infestation. J Drugs Dermatol. 2022;21(7):751-757. doi:10.36849/JDD.6972.

Experimental population modification of the malaria vector mosquito, Anopheles stephensi.

Small laboratory cage trials of non-drive and gene-drive strains of the Asian malaria vector mosquito, Anopheles stephensi, were used to investigate release ratios and other strain properties for their impact on transgene spread during simulated population modification. We evaluated the effects of transgenes on survival, male contributions to next-generation populations, female reproductive success and the impact of accumulation of gene drive-resistant genomic target sites resulting from nonhomologous end-joining (NHEJ) mutagenesis during Cas9, guide RNA-mediated cleavage. Experiments with a non-drive, autosomally-linked malaria-resistance gene cassette showed 'full introduction' (100% of the insects have at least one copy of the transgene) within 8 weeks (≤ 3 generations) following weekly releases of 10:1 transgenic:wild-type males in an overlapping generation trial design. Male release ratios of 1:1 resulted in cages where mosquitoes with at least one copy of the transgene fluctuated around 50%. In comparison, two of three cages in which the malaria-resistance genes were linked to a gene-drive system in an overlapping generation, single 1:1 release reached full introduction in 6-8 generations with a third cage at ~80% within the same time. Release ratios of 0.1:1 failed to establish the transgenes. A non-overlapping generation, single-release trial of the same gene-drive strain resulted in two of three cages reaching 100% introduction within 6-12 generations following a 1:1 transgenic:wild-type male release. Two of three cages with 0.33:1 transgenic:wild-type male single releases achieved full introduction in 13-16 generations. All populations exhibiting full introduction went extinct within three generations due to a significant load on females having disruptions of both copies of the target gene, kynurenine hydroxylase. While repeated releases of high-ratio (10:1) non-drive constructs could achieve full introduction, results from the 1:1 release ratios across all experimental designs favor the use of gene drive, both for efficiency and anticipated cost of the control programs.

nanos-Driven expression of piggyBac transposase induces mobilization of a synthetic autonomous transposon in the malaria vector mosquito, Anopheles stephensi.

Transposons are a class of selfish DNA elements that can mobilize within a genome. If mobilization is accompanied by an increase in copy number (replicative transposition), the transposon may sweep through a population until it is fixed in all of its interbreeding members. This introgression has been proposed as the basis for drive systems to move genes with desirable phenotypes into target species. One such application would be to use them to move a gene conferring resistance to malaria parasites throughout a population of vector mosquitos. We assessed the feasibility of using the piggyBac transposon as a gene-drive mechanism to distribute anti-malarial transgenes in populations of the malaria vector, Anopheles stephensi. We designed synthetic gene constructs that express the piggyBac transposase in the female germline using the control DNA of the An. stephensi nanos orthologous gene linked to marker genes to monitor inheritance. Two remobilization events were observed with a frequency of one every 23 generations, a rate far below what would be useful to drive anti-pathogen transgenes into wild mosquito populations. We discuss the possibility of optimizing this system and the impetus to do so.