This narrative review presents a comprehensive overview of the diagnosis and management of pityriasis versicolor (PV), a common superficial fungal infection caused by the yeast Malassezia. PV is characterised by scaly hypopigmented or hyperpigmented patches, primarily affecting the upper trunk, neck, and upper arms. Regarding commensal interactions, Malassezia utilises nutrient sources without affecting the human host. In cases of pathogenicity, Malassezia can directly harm the host via virulence factors or toxins, or indirectly by triggering damaging host responses. The diagnosis typically relies on recognising characteristic clinical features. Due to the wide variability in its clinical presentation, recognising the differential diagnosis is critical. In this paper, we discuss the clinical differentials, with their dermatoscopic presentation, but also describe a range of helpful diagnostic techniques (microscopy, conventional and ultraviolet-induced fluorescence dermatoscopy, and confocal microscopy). Topical therapies are the primary treatment for PV, encompassing non-specific antifungal agents like sulphur with salicylic acid, selenium sulphide 2.5%, and zinc pyrithione. Additionally, specific topical antifungal medications with either fungicidal or fungistatic properties may also be incorporated into the topical treatment regimen, such as imidazoles, allylamines, and ciclopirox olamine. Systemic therapies might occasionally be used. Patient education and the promotion of good personal hygiene are pivotal to reduce the risk of recurrence. In recurrent cases, particularly during warmer and more humid periods, prolonged prophylaxis with topical agents should be considered.

Tinea incognito is an atypical form of dermatophytosis caused by previous use of topical or systemic immunosuppressive therapy, most often corticosteroids. Modification of the clinical presentation frequently leads to diagnostic delay and misdiagnosis, especially in patients with concomitant chronic inflammatory skin diseases such as psoriasis. We present a narrative review of the literature on tinea incognito in patients with psoriasis during immunosuppressive therapy. We screened 386 abstracts and included 16 comparable case reports focusing on tinea incognito occurring in patients with psoriasis or during antipsoriatic treatment. The review summarizes clinical presentations, diagnostic challenges, and therapeutic approaches reported in the literature. Additionally, we present a clinical case of a 27-year-old man with a long history of plaque psoriasis treated with methotrexate and cyclosporine. The patient developed rapidly progressive skin lesions with pustular features and further deterioration despite systemic antipsoriatic therapy. Initial mycological examinations were negative. Histopathological examination revealed a chronic purulent perifollicular inflammatory process with extension into the subcutaneous tissue. The correct diagnosis was confirmed after a repeat skin biopsy with periodic acid–Schiff and Grocott staining and fungal culture of the skin tissue, which revealed Trichophyton rubrum. The review highlights that clinical features are often nonspecific and may overlap with inflammatory dermatoses. This underscores the need for a high index of clinical suspicion for fungal infection in atypical or refractory psoriatic lesions. It also emphasizes the importance of repeated mycological and histopathological examinations to achieve an accurate diagnosis, avoid inappropriate escalation of immunosuppression, and enable timely antifungal treatment.

Terra firma–forme dermatosis (TFFD) is a benign skin condition characterized by persistent brownish, yellowish, or gray–black patches, primarily affecting children and young adults. Diagnosis is typically clinical but can be enhanced using dermoscopy and ultraviolet‐induced fluorescence dermoscopy (UVFD). This case report presents three patients diagnosed with TFFD, highlighting the unique UVFD patterns observed and the effective management strategies employed. The findings underscore the importance of recognizing TFFD to alleviate patient concerns and prevent unnecessary interventions.

Cutaneous lichen amyloidosis (CLA) is a rare dermatological condition characterized by amyloid deposition in the skin, presenting as pruritic, hyperkeratotic papules. Although most cases are sporadic, CLA has been associated with multiple endocrine neoplasia type 2A (MEN2A), a hereditary syndrome caused by germline alterations in the RET proto-oncogene. In MEN2A, CLA is typically localized to the interscapular region and linked to RET codon 634 variants, whereas generalized forms are rare. We report a male patient with MEN2A and a generalized form of CLA that preceded the diagnosis of primary hyperparathyroidism (PHPT) and medullary thyroid carcinoma (MTC). Genetic testing using Sanger sequencing identified an ultra-rare heterozygous RET variant, p.Y806C, in exon 14, currently classified as a variant of uncertain significance (VUS). This variant has not been previously described in association with MEN2A. This case may contribute to understanding genotype–phenotype correlations in MEN2A and suggests that atypical or generalized CLA may be an early clinical clue warranting consideration of RET genetic testing.

We present the case of a 46-year-old woman with a long-standing history of linear erythematosquamous papules on the arms and thighs, which were unresponsive to treatment with topical corticosteroids. She also reported lesions typical of seborrheic dermatitis located on her face. After performing a clinical examination, dermatoscopy, high-frequency ultrasonography (HFUS), and a biopsy for histopathological examination, a diagnosis of keratosis lichenoides chronica (KLC) was obtained. Also known as Nekam disease, KLC is a rare, chronic inflammatory skin disease characterized by diffuse, linearly arranged erythro- or erythematosquamous papules with a thin, keratotic plug.

Introduction Cutaneous lupus erythematosus is a chronic inflammatory autoimmune disease of multifactorial etiology. In every form of cutaneous lupus erythematosus, there is a risk of progression to systemic lupus erythematosus at any stage of the disease. Its development is influenced by...