The expression of pruritus‐associated genes in seven skin diseases: Evidence from microarray

Background Pruritus may accompany different skin diseases including atopic dermatitis, lichen planus, psoriasis, cutaneous lupus erythematosus, acne, alopecia areata and rosacea. Objectives This study aims to investigate the expression of pruritus‐associated genes in the above‐mentioned seven skin diseases. Methods We searched the Gene Expression Omnibus database and retrieved microarray data sets for the respective skin diseases. We searched the Gene Set Enrichment Analysis–Molecular Signatures database to obtain the pruritus‐associated gene set. We examined the expression of the pruritus‐associated genes in the microarray data sets to identify the differentially expressed genes compared to healthy controls. Results We retrieved 147 pruritus‐associated genes from the Gene Set Enrichment Analysis‐Molecular Signatures database and analysed their expression in nine data sets, representing seven skin diseases and totalling biopsies collected from 80 healthy individuals and 208 lesional skin. We found the top differentially upregulated pruritus‐associated genes were CLEC7A , IL7R and TNFRSF1B in acne; HLA‐DRA , IL2RG and POU2AF1 in alopecia areata; IL2RG , PLEC and CTLA4 in atopic dermatitis; CLEC7A , IL7R and LIPA in cutaneous lupus erythematosus; HLA‐DRA , ABCA12 and IL7R in lichen planus; CLEC7A , TGM1 and SDR9C7 in psoriasis and IL7R , HLA‐DRB1/HLA‐DRB3/HLA‐DRB4/HLA‐DRB5 /LOC105369230 and POU2AF1 in rosacea. Conclusions While some genes are shared among these diseases, others are unique to each condition. Our findings emphasize the complexity of itch pathogenesis and highlight the importance of personalized treatment for each patient. It also lays the groundwork for studying pruritus‐associated genes on a genomic level to identify the therapeutic targets tailored to each disease.