Allergic Contact Dermatitis of the Scalp Associated With Scalp Applied Products: A Systematic Review of Topical Allergens.

ABSTRACT: Hair products are commonly used to maintain hair health or cosmesis. Products applied to the scalp and hair contain multiple active and inactive ingredients that can potentially cause irritant and/or allergic contact dermatitis. The objectives of this study were to identify and to discuss the most common allergens in scalp and hair applied products causing scalp allergic contact dermatitis (ACD). A PubMed search identified 99 studies, with 3185 patients and 31 categories of scalp products. Hair products reportedly associated with scalp ACD were hair dyes (41%), shampoos (28%), and conditioners (22%). The most commonly reported patch test-positive allergens were p -phenylenediamine (23%), nickel (15%), fragrance mix (13%), balsam of Peru (10%), cocamidopropyl betaine/3-dimethylaminopropylamine (7%), and methylchloroisothiazolinone/methylisothiazolinone (6%). Common symptoms and signs include eczematous lesions, pruritus, and a burning sensation. Medical practitioners should be aware of causative agents to provide appropriate patient education, counseling, and/or treatment.

The Association of Frontal Alopecia with a History of Facial and Scalp Surgical Procedures.

INTRODUCTION: The prevalence of frontal fibrosing alopecia (FFA) is increasing worldwide, though the pathogenesis remains unknown. Anecdotal reports describe alopecia occurring in an FFA pattern following facial surgical procedures, but this potential link remains unexplored. OBJECTIVE: The objective of this study is to determine if a significant association exists between the diagnosis of FFA and a history of facial and scalp surgical procedures. METHODS: This retrospective study comparing data from frontal alopecia patients to controls was conducted at a tertiary medical center. Additionally, a literature review was conducted on scarring alopecias occurring from scalp procedures. RESULTS: Fifty percent of frontal alopecia patients (n = 54) reported a history of facial surgical procedures compared to 9.8% of controls (n = 51) (OR: 7.8 [95% CI: 2.77-25.98, p < 0.001]). Although no significant differences were observed in current daily facial sunscreen use, sunscreen use prior to alopecia onset was significantly higher in frontal alopecia (p = 0.295; p = 0.021). Sunscreen use was not a significant modifier in the association between frontal alopecia and facial surgical procedures (p = 0.89). CONCLUSIONS: A significant association exists between frontal alopecia clinically consistent with FFA and a history of facial surgery, the nature of which is unclear. The role of sunscreen use and frontal alopecia development in this setting needs to be better elucidated.

A Systematic Review: Application of Rice Products for Hair Growth.

BACKGROUND: Rice bran extracts (RB) derived from Oryza sativa are part of cultural skin and hair care practices in Asia. Given the knowledge gap regarding clinical efficacy, marketplace availability, and safety, the growing popularity of nutraceuticals calls for better clinician awareness and scientific understanding of their applications and limitations. OBJECTIVE: To review available scientific evidence regarding therapeutic efficacy, safety, and consumer availability of RB on hair health. MATERIALS AND METHODS: A primary literature search was conducted using PubMed to identify articles on RB and hair growth in May 2021. A limited market analysis of rice-derivative-containing hair products was also conducted on Amazon.com. RESULTS: 10 studies were analyzed: six regarding the efficacy of RB for hair growth, and four analyzing the safety profile of RB. Topically applied RB increases expression of growth factors and molecular signals which promote cell proliferation in the anagen phase including β-catenin, while inhibiting enzymes responsible for propagating anagen to catagen/telogen transition including TGFβ and Type I 5α-reductase. RB is non-genotoxic, non-cytotoxic, and appropriate for human use in cosmetics. The Amazon.com search yielded 119 rice-containing hair products, reflecting their over-the-counter popularity. CONCLUSIONS: Current literature is promising for RB promoting hair growth given its ability to increase expression of growth factors and molecular signals associated with maintaining anagen phase, decreasing inflammation, inhibiting 5α-reductase, and promoting melanogenesis. J Drugs Dermatol. 2022;21(2):177-185. doi:10.36849/JDD.6345.

Combining Deep Learning With Optical Coherence Tomography Imaging to Determine Scalp Hair and Follicle Counts.

BACKGROUND AND OBJECTIVES: One of the challenges in developing effective hair loss therapies is the lack of reliable methods to monitor treatment response or alopecia progression. In this study, we propose the use of optical coherence tomography (OCT) and automated deep learning to non-invasively evaluate hair and follicle counts that may be used to monitor the success of hair growth therapy more accurately and efficiently. STUDY DESIGN/MATERIALS AND METHODS: We collected 70 OCT scans from 14 patients with alopecia and trained a convolutional neural network (CNN) to automatically count all follicles present in the scans. The model is based on a dual approach of both detecting hair follicles and estimating the local hair density in order to give accurate counts even for cases where two or more adjacent hairs are in close proximity to each other. RESULTS: We evaluate our system on 70 OCT manually labeled scans taken at different scalp locations from 14 patients, with 20 of those redundantly labeled by two human expert OCT operators. When comparing the individual human predictions and considering the exact locations of hair and follicle predictions, we find that the two human raters disagree with each other on approximately 22% of hairs and follicles. Overall, the deep learning (DL) system predicts the number of follicles with an error rate of 11.8% and the number of hairs with an error rate of 18.7% on average on the 70 scans. The OCT system can capture one scalp location in three seconds, and the DL model can make all predictions in less than a second after processing the scan, which takes half a minute using an unoptimized implementation. CONCLUSION: This approach is well-positioned to become the standard for non-invasive evaluation of hair growth treatment progress in patients, saving significant amounts of time and effort compared with manual evaluation. Lasers Surg. Med. © 2020 Wiley Periodicals, Inc.