Background: Alopecia is a common chief complaint and is challenging to treat. As such, regenerative treatments to promote hair growth are an emerging area of research. Exosomes, which are extracellular vesicles involved in cell communication, homeostasis, differentiation, and organogenesis, have been shown to play a central role in hair morphogenesis and regeneration with potential for use as alopecia treatment.Aims: This review summarizes and assesses the body of literature surrounding exosomes as regenerative therapeutics for alopecia and identifies areas for improvement in future research.Methods: A review was conducted using a comprehensive list of keywords including "exosome," "alopecia," and "hair loss" on PubMed, EMBASE, and Google Scholar databases published from inception to February 2022. Reference lists of identified articles were included. 47 studies were included. Clinical trial databases were searched using the term "exosome"; however, no trials relevant to hair growth were identified.Results: Our updated and comprehensive review details the history of exosome use in medicine, postulated underlying mechanisms in treating hair loss, and current clinical studies. Preclinical studies demonstrate clear benefits of exosome therapeutics in regenerative medicine and for hair loss treatment. Clinical trials demonstrate safety of exosome use in medicine, but data showing efficacy and safety of exosome therapy for alopecia are lacking. We identified several gaps in knowledge required for effective clinical translation including safety, exosome source, and optimal treatment delivery mechanism and dosage. Conclusion:Exosomes are on the horizon as an exciting therapeutic for the treatment of alopecia. Further studies and clinical trials are required.

Background: Melasma is a disorder of hyperpigmentation and vascularization often found in women between the ages of 20 and 40. The pathogenesis is unknown, but melasma often occurs in sun-exposed areas of the face, forearms, and back. Risk factors include family history, increased estrogen/progesterone, certain medications, and UV exposure. Melasma is typically treated with topical hydroquinone (HQ); however, it is often refractory to treatment. Tranexamic acid (TXA) is a plasmin inhibitor used off-label in the treatment of melasma. TXA can be administered orally, topically, or intralesionally. Aims:The purpose of this review is to characterize the wide variety of TXA delivery methods for melasma treatment and the efficacy of these methods compared with traditional treatments.Patients/Methods: A comprehensive PubMed and Embase search was conducted in May 2022 using the phrases tranexamic acid and melasma. Forty-six articles were included in this review.Results: Oral, intralesional, and topical TXA is safe and effective treatments for melasma. They have been studied in a variety of randomized controlled trials and have been compared with several traditional treatments. Overall, MASI scores in patients using TXA in any form improved. Conclusions:Oral TXA was found to be the most effective, especially in cases of refractory melasma; however, it caused GI upset and menstrual irregularities in many patients. The pro-thrombotic nature of this drug must be considered before safely prescribing to patients. Intralesional injections and microneedling with topical TXA were found to be effective alternatives to oral treatment. Lastly, topical TXA alone was found to be the least effective method but can be combined with other cosmeceuticals to improve outcomes. Topical TXA was also found to be better tolerated than hydroquinone, a traditional topical melasma treatment.

Pentoxifylline was initially marketed for use in patients with intermittent claudication due to chronic occlusive arterial disease of the extremities but has since been shown to have several off-label uses. It can be described chemically as 1-(5-oxohexyl)-3, 7-dimethylxanthine, which is a tri-substituted xanthine derivative. 1 Pentoxifylline has a variety of mechanisms of action (Figure 1). In its original purpose, it was used because of its rheological modifying properties, such as increasing the deformability of erythrocytes