The concept of a second skin or electronic skin (e-skin) is currently a hot topic, reflecting technological advances in electronics, polymers, and nanotechnology, but this subject has not yet reached the mainstream of skin biologists, dermatologists, and the wider medical community. These recently developed devices are proving to be useful in monitoring systemic health across the skin surface with far greater precision than typical electrode-based devices. Moreover, e-skins are being designed to extract and monitor samples of body fluids continuously as well as to improve transdermal drug delivery.

Itch is a common symptom of skin conditions such as psoriasis (Elewski et al., 2019). The processing of itch-related information can be influenced by implicit processes such as biased avoidance tendencies (Silverberg et al., 2018; Verhoeven et al., 2006) and attentional biases (Evers et al., 2019; van Laarhoven et al., 2020), which can amplify the sensation of itch. These processes can especially affect those with chronic itch and their significant others (SOs), because they may be exposed to itch-related stimuli more often than the general public.

In September 2022, Agelopoulos et al. (2023) published an investigation on the density and distribution of intraepithelial sensory nerve fibers using pan-neuronal marker, protein gene product 9.5, in skin biopsies from patients with chronic nodular prurigo (CNPG), atopic dermatitis (AD), and brachioradial pruritus (BRP) and from healthy controls. In addition to a reduced number of intraepidermal nerve fibers in biopsies from all patients compared with those from healthy controls, different neuronal branching patterns were recognized in CNPG, BGP, and AD (Agelopoulos et al., 2023).

In their recent paper, Almet et al. (2023) provide a framework for the research community aiming to standardize single-cell datasets and find common terminology to more accurately describe cutaneous cell populations and functional cell states. More specifically, the authors propose to construct a Human Skin Cell Atlas mainly derived from single-cell RNA-sequencing studies as part of a worldwide consortium organized by and integrated into the Human Cell Atlas Initiative. As challenging as it may sound, such an undertaking is necessary and worthwhile because it will help to deconvolute complex datasets for the benefit of clarity and reproducibility in cutaneous research.

Hair shafts are formed by a special mode of keratinocyte (KC) differentiation (Harland and Plowman, 2018), which is characterized by the accumulation of hair keratins (keratin [K]31–K40, K81–K90) and keratin-associated proteins, cell death by cornification, and integration of the dead cells into the growing hair shaft (Jones et al., 2018) (Figure 1a). The death of hair KCs is associated with the breakdown of the nucleus and other organelles (Fischer et al., 2011; Jones et al., 2018). Autophagy is a major intracellular degradation process that is controlled by autophagy-related genes (Mizushima and Komatsu, 2011).