Figure 1.

Skin functions affected by acute stressors. 1. The skin physical barrier or stratum corneum, consisting of differentiated keratinocytes (corneocytes) encased in lipid lamellae and tight junctions, is important for lipid synthesis, skin hydration and desquamation that play a role in skin dryness, tightness and skin sensitivity. 2. Melanocytes and interacting keratinocytes have a key role in skin pigmentation. 3. Skin biochemical defences have a role in antioxidant response, osmolyte strategy, DNA repair and pain, while immune/cellular defences have a role in skin immunity, including inflammation (e.g. in exacerbation of psoriasis, atopic dermatitis, seborrhoeic dermatitis, acne), Langerhans cells, decreased immunity with risk of superinfection and alteration of the skin microbiome (e.g. reactivation of viral infections under psychological stress and UV radiation). 4. The skin structure including the extracellular matrix and adnexa (hair follicles, sebaceous glands, sweat glands) plays a role in hypersudation and development of telogen effluvium. 5. Skin neuroendocrine delivery by vasculature and innervation involves local production of neurotransmitters, neurotrophins, neuropeptides, hormones with a role in the neurogenic inflammation (e.g. pain and pruritus), triggering the HPA axis, increased endocrine, vegetative and neuropeptidergic excitability levels. 6. The thermoregulation function involving blood vessels and fat has a role in vasoconstriction and flushes (e.g. rosacea)