Search

Blue nevi are benign proliferations of melaninproducingdendritic melanocytes located in thedermis. These nevi tend to occur mostly on the skin,predominantly on the head and neck, dorsal aspectsof the distal extremities, and the sacral area, butcan also occasionally appear on mucosal surfaces.Blue nevi of the nail apparatus are uncommon. Themajority originate in the nail matrix where there is ahigher density of melanocytes. Herein we report ona 47-year-old man with a rare common blue nevus ofthe nail bed, an area with low melanocyte density. Athorough review of the English language literaturefound no documented cases of acquired blue nevioriginating in the nailbed of the toe.

Psoriasis vulgaris and other chronic inflammatory diseases improve markedly with therapeutic blockade of interleukin-23 (IL-23) signaling, but the genetic mechanisms underlying clinical responses remain poorly understood. Using single-cell transcriptomics, we profiled immune cells isolated from lesional psoriatic skin before and during IL-23 blockade. In clinically responsive patients, a psoriatic transcriptional signature in skin-resident memory T cells was strongly attenuated. In contrast, poorly responsive patients were distinguished by persistent activation of IL-17–producing T (T17) cells, a mechanism distinct from alternative cytokine signaling or resistance isolated to epidermal keratinocytes. Even in IL-23 blockade–responsive patients, we detected a recurring set of recalcitrant, disease-specific transcriptional abnormalities. This irreversible immunological state may necessitate ongoing IL-23 inhibition. Spatial transcriptomic analyses also suggested that successful IL-23 blockade requires dampening of >90% of IL-17–induced response in lymphocyte-adjacent keratinocytes, an unexpectedly high threshold. Collectively, our data establish a patient-level paradigm for dissecting responses to immunomodulatory treatments. Editor's summary: Although the underlying cause of psoriasis is not completely understood, therapies that suppress the activity of IL-17–producing T (T17) cells have achieved broad clinical success. Using single-cell transcriptomics of skin biopsies collected from patients with psoriasis, Wu et al. examined the molecular basis of responses to IL-23 blockade. Patients who successfully responded to treatment showed reduced abundance of T17 cells and partial correction of psoriasis-specific gene expression. Even in patients displaying a strong clinical response to IL-23 blockade, a portion of the psoriatic T17 transcriptional identity persisted, although less than in poor responders. Conversely, successful response was associated with a greater than 90% attenuation of an IL-17–induced keratinocyte transcriptional signature. This study provides insight into single-cell resolution into the immunological drivers of cutaneous psoriasis and underlying clinical responses to IL-23 blockade. —Claire Olingy [ABSTRACT FROM AUTHOR]

Hidradenitis suppurativa (HS) is a complex, chronic skin disease characterised by painful inflammatory nodules, abscesses, dermal tunnels, sinus tracts and fistulae with a predilection for intertriginous skin. HS carries a substantial disease burden due to its prevalence, associated comorbidities and quality of life impacts and is associated with high healthcare resource utilisation. Clarity regarding the prevalence and pathogenesis of HS has led to improved therapies and more patients seeking care in both outpatient and acute care settings, including the emergency department. Emergency medicine providers play a critical role in HS diagnosis, management of acute flares and connection of HS patients with long-term dermatologic care, which can in turn help manage utilisation of acute care resources., Competing Interests: Competing interests: HN has received grant support from AbbVie; consulting fees from 23andme, AbbVie, Aristea Therapeutics, Nimbus Therapeutics, Medscape, Sonoma Biotherapeutics, DAVA Oncology, Boehringer Ingelheim, Union Chimique Belge and Novartis; investigator fees from Pfizer; and holds shares in Radera. She is also an associate editor for JAMA Dermatology and a board member of the Hidradenitis Suppurativa Foundation., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Palmoplantar psoriasis is a chronic debilitating type of psoriasis. Treatment options for this disease are poorly studied. This chart review evaluated the use of methotrexate alone and in combination with 7 other systemic therapies in 48 patients with palmoplantar psoriasis. The findings demonstrate that methotrexate is a relatively well-tolerated and effective treatment for palmoplantar psoriasis, amenable as either monotherapy or in combination with other systemic agents.