Effect of ultraviolet light on topical minoxidil-induced hair growth in advanced male pattern baldness

Allergic Contact Dermatitis to Topical Preparations Containing Minoxidil: A Systematic Review and Individual Participant Data Meta-Analysis

Topical minoxidil is generally well tolerated, yet there have been a few reports of allergic contact dermatitis (ACD) confirmed through patch testing. This systematic review and individual participant data meta-analysis sought to elucidate the primary allergens in patients exhibiting ACD in response to topical minoxidil formulations and to ascertain the appropriate testing concentrations and vehicles of minoxidil itself. A comprehensive search was conducted across the PubMed, Scopus, and Embase databases utilizing the keywords "minoxidil" and "contact dermatitis," or "contact allergy," or "contact eczema." Studies documenting ACD in patients using topical minoxidil confirmed by patch testing were deemed eligible. Our analysis included 46 studies encompassing 99 patients with patch-test-confirmed ACD to minoxidil-based topical treatments. The majority of these patients (93.9%) were exposed to minoxidil without additional active components. Minoxidil itself was identified as the primary allergen in 74.7% of the patients, with propylene glycol being the next most common allergen at 17.1%. Other allergens identified included estradiol, butylene glycol, methylchloroisothiazolinone/methylisothiazolinone, canrenone, and latanoprost. The most effective concentration was found to be 2% minoxidil in propylene glycol, which yielded a 100% positivity rate. The findings indicate that minoxidil is the predominant allergen in ACD reactions to its topical formulations, followed by propylene glycol. For the accurate diagnosis of ACD related to minoxidil, patch testing with 2% minoxidil in propylene glycol is recommended, as are separate tests for propylene glycol and other potential allergenic ingredients.

Management of androgenic alopecia: a systematic review of the literature

We aimed to determine the efficacy of the various available oral, topical, and procedural treatment options for hair loss in individuals with androgenic alopecia. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a systematic review of the National Library of Medicine was performed. Overall, 141 unique studies met our inclusion criteria. We demonstrate that many over the counter (e.g. topical minoxidil, supplements, low-level light treatment), prescription (e.g. oral minoxidil, finasteride, dutasteride), and procedural (e.g. platelet-rich plasma, fractionated lasers, hair transplantation) treatments successfully promote hair growth, highlighting the superiority of a multifaceted and individualized approach to management.

Effect of Skin Type on Efficacy of Laser Treatment for Androgenetic Alopecia: A Review of the Literature

The use of low-light laser therapy to treat androgenetic alopecia is a promising modality to restore hair growth. However, the effect of skin color on response to laser therapy for hair growth has not been systematically explored in the literature. The objective of this study is to systematically assess through a comprehensive literature search of the MEDLINE database whether skin type data were collected in clinical trials and analyzed in each study and determine if we can estimate an effect. 10/22 studies have defined inclusion criteria as Fitzpatrick skin types I-IV. No studies mentioned effects on darker skin types, Fitzpatrick skin types V-VI. Only 5/10 studies had statistical data on efficacy depending on Fitzpatrick skin type, with four showing no effect and one showing a significant positive effect with darker skin types having faster rate of hair growth. There are not enough data to conclude whether skin type effects laser-induced hair growth in androgenic alopecia. The studies are severely lacking in sample size. One showed a potential effect. Importantly, there are no data on black or brown skin colors. Development of optimal laser irradiating wparameters through the prediction of personalized absorbance based on skin color measurement is needed.