Seborrheic dermatitis (SD) is a chronic inflammatory skin condition likely caused by several factors, including overgrowth of the lipophilic yeast Malassezia, increased sebaceous gland activity, and a potential genetic predisposition, whereas Malassezia folliculitis (MF) is a fungal infection of hair follicles. In this case, a 22-year-old male initially presented with erythematous papules on the malar region and was clinically diagnosed with SD. Following partial improvement with topical and oral antifungals, the patient developed new pustular lesions involving the malar and chin regions, raising suspicion of MF. The absence of comedones and cysts helped rule out Acne vulgaris. Potassium hydroxide mount from pustular swabs revealed numerous fungal spores, prompting further investigation. Culture on modified Leeming and Notman agar yielded yeast colonies, which appeared as budding yeast cells under light and fluorescence microscopy with Calcofluor white stain. Molecular identification using PCR for the ITS regions and RFLP analysis confirmed the isolate as Malassezia furfur. This case highlights the clinical progression from SD to MF, underscoring the pathogenic potential of Malassezia and the importance of integrating clinical, microscopic, and culture-based molecular diagnostic approaches for accurate diagnosis and targeted treatment in dermatological mycoses.

A 49-year-old female presented with redness and scaling of scalp of 2 years duration. It was associated with photosensitivity and difficulty getting up from squatting position since 4 months. Written informed consent was obtained from the patient who agreed to take part in the study. Clinical examination revealed diffuse uniform erythema affecting scalp and its margins at forehead, temples and posterior aspect of neck. Cite this article as: Das P., Bhatnagar A, Sharma S, et al. Seborrheic dermatitis-like presentation of dermatomyositis. Eur J Rheumatol. 13(1), 0009, doi: 10.5152/eurjrheum.2026.25009.

Seborrheic dermatitis (SD) is a chronic relapsing inflammatory dermatosis closely associated with Malassezia furfur overgrowth. Given the growing interest in metal-based antimicrobials, copper compounds were investigated here as potential anti-Malassezia agents for SD treatment. CuSO4 showed the strongest antifungal activity against M. furfur at 1 mM and rapidly reduced fungal viability. Mechanistic analyses revealed intracellular copper accumulation, elevated Fe[2+] levels, increased reactive oxygen species generation, and enhanced lipid peroxidation, collectively suggesting an oxidative damage pattern with ferroptosis-like features. Based on its potent anti-Malassezia activity, a CuSO4-loaded xanthan gum/hyaluronic acid hydrogel (HG-Cu) was further developed for integrated local treatment of seborrheic dermatitis. HG-Cu exhibited viscous-flow behavior, high structural stability, and favorable biocompatibility. In a guinea pig model of M. furfur-induced seborrheic dermatitis, HG-Cu effectively suppressed fungal proliferation in lesions through sustained copper release. Histopathological analysis showed that HG-Cu markedly ameliorated skin lesions, reduced inflammatory infiltration, and promoted matrix reconstruction and skin repair by upregulating type III collagen (COL III) at the early stage and enhancing type I collagen (COL I) deposition at the later stage. Taken together, HG-Cu offers a promising localized therapeutic approach for seborrheic dermatitis by integrating sustained antifungal activity, inflammation control, and skin barrier restoration.

Inflammatory skin diseases (ISDs) represent a significant global health burden, yet the role of the human microbiome in their pathogenesis remains unclear. This study employed a comprehensive two-sample Mendelian randomization (MR) framework to investigate potential causal associations between multi-site microbiota (3117 oral, 412 gut, and 150 skin microbial features) and five major ISDs: psoriasis, atopic dermatitis, acne, seborrheic dermatitis, and urticaria. Genetic instruments were selected from large-scale genome-wide association studies (GWAS) of microbiota composition and ISD outcomes. The inverse variance weighted (IVW) method served as the primary analytical approach, supplemented by MR-Egger regression, weighted median, and MR-PRESSO for sensitivity analyses. Multiple testing was controlled using the false discovery rate (FDR) method. Our analyses identified numerous suggestive associations between specific microbial taxa, metabolic pathways, and ISD risk. Notably, shared microbial signatures were observed across multiple ISDs, suggesting potentially shared microbiome-associated pathogenic pathways. These results provide genetic evidence supporting a role for the microbiome in ISD susceptibility and highlight potential microbial targets for future therapeutic development.

Microbiome refers to the collection of microorganisms living in the human body. Skin, intestines and upper respiratory tract are particularly inhabited by microorganisms. The microbiota of the scalp and hair, though so far little understood, is particularly abundant in terms of microorganisms, which play an important role in maintaining the health of the scalp by inhibiting pathogens and promoting optimal skin condition. Dysbiosis of the scalp microbiota can be influenced by many factors, both exo and endogenous leading to the development of pathological conditions such as dandruff or seborrhoeic dermatitis. The aim of this preliminary study was the microbiological diagnosis of the scalp and hair in the group of individuals aged 20-40 years old. The samples for the research have been obtained from three different sites on the scalp of 6 individuals aged 20 to 40. The material for the study was collected using contact plates for total bacterial counts - Rodac Contact Test. The colonies grown on the microbiological media were characterised in terms of their size and shape. Subsequently, Gram staining was performed to assign the colonies of the bacteria to Gram-positive or Gram-negative bacteria, as well as fungi characterisation of the scalp and hair was conducted using a trichological camera. Finally, on the basis of the study following conclusions have been drawn. There were observed differences in the appearance of microbial colonies between younger and older people and in the group of 40-year-old, there was a significantly less colony diversity monitored. In terms of bacteria, Gram-positive cocci got isolated most frequently. In addition, yeast as well as filamentous fungi occurred abundant in the middle of the head of the research participants.