Skin inflammation is a common underlying feature of atopic dermatitis, allergic contact dermatitis and chronic spontaneous urticaria. The pathogenetic mechanisms have not been fully elucidated. The purpose of this study was to examine whether miRNA, by regulating inflammatory mechanisms through the modulation of innate and adaptive immune responses, could play a major role in the pathogenesis of these skin conditions. We conducted a narrative review using the Pubmed and Embase scientific databases and search engines to find the most relevant miRNAs related to the pathophysiology, severity and prognosis of skin conditions. The studies show that miRNAs are involved in the pathogenesis and regulation of atopic dermatitis and can reveal an atopic predisposition or indicate disease severity. In chronic spontaneous urticaria, different miRNAs which are over-expressed during urticaria exacerbations not only play a role in the possible response to therapy or remission, but also serve as a marker of chronic autoimmune urticaria and indicate associations with other autoimmune diseases. In allergic contact dermatitis, miRNAs are upregulated in inflammatory lesions and expressed during the sensitization phase of allergic response. Several miRNAs have been identified as potential biomarkers of these chronic skin conditions, but they are also possible therapeutic targets.

Lysosomal storage disorders (LSDs) are a heterogeneous group of about 70 different rare diseases characterized by different types of genetic impairment leading to partial or complete loss of specific enzymes, resulting in metabolite accumulation in the lysosomes. The resulting cell damage leads to an impairment of tissues or organs, determining the clinical signs and symptoms. 1 The genetic defect may be transmitted in an autosomal recessive or X-linked recessive manner. Life expectancy can range from a few years to a normal life span (albeit with a significantly reduced quality of life).The estimated incidence of individual LSDs ranges from 1 in 50,000 to 1 in 250,000 live births, with a cumulative estimated incidence (including all the different LSDs) of about 1 in 5500. The most prevalent LSDs are Pompe disease (up to 2.5 cases per 100,000 males), Fabry disease (up to 2.5 cases per 100,000 people), Gaucher disease (up to two cases per 100,000 people), and metachromatic leukodystrophy (up to 2.5 cases per 100,000 people). [2][3][4]