[Atypical presentation of penile blue naevus].

Blue naevus is a rare lesion on genital mucosa and may cause confusion in differential diagnosis with other pigmented lesions. In this case report, a 39-year-old man presented with a sudden onset in adulthood of blue naevus on the glans penis. A biopsy confirmed the diagnosis. Due to the unusual presentation, the onset and the risk of turning invasive, a careful examination was performed in order to minimise any risk of misclassification with melanoma. Afterwards, the patient was followed in a dermatologic department every six months. To our knowledge, only few similar cases have been described in literature.

Skin barrier damage after exposure to paraphenylenediamine.

BACKGROUND: p-Phenylenediamine (PPD) is a strong contact allergen used in hair dye that is known to cause allergic contact dermatitis (ACD). Both private and occupational exposure to PPD is frequent, but the effect of PPD exposure in nonallergic occupationally exposed subjects is unknown. OBJECTIVE: We sought to investigate the effects of PPD exposure on the skin of occupationally exposed subjects with and without clinical symptoms. METHODS: Skin biopsy specimens were collected from 4 patients with mild and 5 patients with severe PPD-related ACD and 7 hairdressers without contact dermatitis on day 4 after patch testing with 1% PPD in petrolatum. RNA sequencing and transcriptomics analyses were performed and confirmed by using quantitative RT-PCR. Protein expression was analyzed in skin from 4 hairdressers and 1 patient with ACD by using immunofluorescence staining. Reconstructed human epidermis was used to test the effects of PPD in vitro. RESULTS: RNA sequencing demonstrated downregulation of tight junction and stratum corneum proteins in the skin of patients with severe ACD after PPD exposure. Claudin-1 (CLDN-1), CLDN8, CLDN11, CXADR-like membrane protein (CLMP), occludin (OCLN), membrane-associated guanylate kinase inverted 1 (MAGI1), and MAGI2 mRNA expression was downregulated in patients with severe ACD. CLDN1 and CLMP expression were downregulated in nonresponding hairdressers and patients with mild ACD. Filaggrin 1 (FLG1), FLG2, and loricrin (LOR) expression were downregulated in patients with ACD. Confocal microscopic images showed downregulation of CLDN-1, FLG-1, and FLG-2 expression. In contrast, 3-dimensional skin cultures showed upregulation of FLG-1 in response to PPD but downregulation of FLG-2. CONCLUSION: PPD-exposed skin is associated with extensive transcriptomic changes, including downregulation of tight junction and stratum corneum proteins, even in the absence of clinical symptoms.