Picosecond lasers are gaining increasing popularity in dermatology and aesthetic medicine due to their favorable safety profile and a wide range of therapeutic applications. While originally employed primarily for tattoo removal, their versatility has extended their use to the treatment of various aesthetic skin conditions, including hyperpigmentation, acne scars, stretch marks, and signs of photoaging. Owing to their ultra-short pulse duration, picosecond lasers effectively target pigment particles and stimulate dermal remodeling, offering patients a safe and effective solution to improve the appearance of their skin. The introduction of the picosecond laser into clinical dermatology practice marks a notable advancement in addressing a broad spectrum of skin problems.

Human hair performs a number of important physiological and esthetic functions. Hair loss and alopecia are complex disorders which affect people all over the world. Hair loss can be an early manifestation of various autoimmunological disorders. Despite a growing interest of researchers in the role of immune factors—especially autoantibodies—in the etiology of certain types of alopecia, their role in alopecia remains uncertain. Several potential autoantigens of follicular components, mainly derived from keratinocytes and melanocytes of the hair follicles, have been found to play a role in the development of alopecia areata. The list of autoantigens includes trichohyalin, keratin 16, fibroblast growth factor receptor 3, glycoprotein-100, melanoma-associated antigen recognized by T cells 1, dopachrome tautomerase/tyrosinase-related protein 2, tyrosinase, and tyrosine hydroxylase. This narrative review presents different aspects of immunopathogenesis of alopecia, from physiology (hair follicle immune privilege) to pathology (disruption of hair follicle immune privilege) and signaling pathways. Identification of key autoantigens could potentially pave the way for the development of new, effective, and more targeted immunotherapies for alopecia.

Retinol, a bioactive small molecule of the vitamin A family, contributes epidermal and dermal tissue repair through retinoic acid receptor γ (RARγ)/retinoid X receptor (RXR) receptor-mediated transcriptional regulation of keratinocyte differentiation, extracellular matrix (ECM) remodeling, and barrier restoration. However, the relationship between applied concentration, tissue-level regenerative outcomes, and tolerability remains incompletely characterized. This prospective, randomized, single-blind study compared biophysical effects and tolerance of two retinol concentrations in EU-compliant facial creams, high-performance liquid chromatography (HPLC)-verified as 0.104% and 0.247% (w/w). Thirty-eight women aged 40–61 years (Fitzpatrick phototypes II–III) participated across three independent sub-studies: 28 were randomized to either concentration for 12 weeks; 5 underwent split-face ultrasound imaging (0.247% versus retinol-free control) for 8 weeks; and 5 participated in a tape stripping sub-study quantifying stratum corneum interleukin-1 alpha (IL-1α) and interleukin-1 receptor antagonist (IL-1ra) by ELISA before and after 6 weeks of 0.247% retinol treatment. Main cohort assessments included transepidermal water loss (TEWL), hydration, melanin, erythema, pH, sebum, biomechanical parameters, and wrinkle grading. Both concentrations significantly improved barrier parameters—hydration, TEWL, brightness, pH, and sebum—with no inter-group differences. In the ultrasound sub-group, 0.247% retinol increased epidermal thickness (+12.4 μm), epidermal density (+3.84%), and dermal density (+1.81%) versus control, consistent with ECM reorganization and epidermal stratification. Biomechanical parameters showed no significant changes, consistent with retinol’s remodeling timeline. Consumer assessment indicated comparable efficacy; 0.247% demonstrated superior smoothing but higher erythema incidence. In the tape stripping sub-study, IL-1α decreased in all participants (median: 25.1 → 13.2 picograms per tape [pg/Tape]; 5/5 concordant), while IL-1ra increased in 4/5 participants (median: 352.8 → 1403.1 picograms per three sequential tapes [pg/3sT]), indicating a directionally consistent shift in the IL-1α/IL-1ra balance; these results are exploratory and require replication in larger cohorts. These findings collectively support clinically meaningful barrier restoration and structural remodeling within current EU safety limits (Commission Regulation EU 2024/996), with 0.104% offering a favorable efficacy-to-tolerability profile for initial therapy.