Annular lesions in dermatology

A clinical prevalence of dermatophytic mycoses with an assessment of its clinical manifestations in a tertiary care hospital at Salem, South India

BACKGROUND

Dermatophytosis is very common among all age groups throughout the world. The incidence of the same is increasing on a steady basis.

AIM

Estimating the clinical prevalence of dermatophytes mycoses among the patients visiting the outpatient unit and assessing its distinct manifestations.

METHODOLOGY

A prospective observational study was conducted with the patients attending the Skin and STD outpatient unit of a tertiary care teaching hospital in Salem. A total of 3068 outpatients attended the department, of which 420 patients were diagnosed with dermatophytic mycoses and were taken for investigating the prevalence.

RESULTS

A total of 420 dermatophytosis patients were included giving a percentage prevalence of 13.69%. There were more female patients (n = 213, 50.71%) than males (n = 207, 49.29%). The most common afflicted age group was 31-40 years (n = 99, 50.71%). Most of the patients had an atypical lesion called tinea incognita (n = 265, 63.09%) where there was no typical classic appearance of dermatophytic infections. The most prevalent clinical manifestation was tinea corporis (n = 73, 17.38%) followed by tinea cruris (n = 69, 16.43%). There were more newly diagnosed dermatophytosis cases (n = 326) than the previously diagnosed cases (n = 94).

CONCLUSION

This study concludes that dermatophytic mycoses were more prevalent among females than males and among the age groups of 31-40 years. The most common clinical presentation was tinea incognita followed by tinea corporis.

Annular skin tumors and lymphoproliferative diseases

Determining the shape of a skin lesion may provide a diagnostic clue in dermatology practice, more commonly for inflammatory diseases but also for skin tumors. The annular formation may develop by diverse mechanisms in skin tumors. Annular lesions may occur from the onset of the tumor as sparing the central area or depression and/or ulceration in the center of the tumor or outward expansion of the primary lesion. Clustering of multiple papulonodular lesions sparing the central area or relatively independent processes acting on the central and peripheral components of the tumor may also result in an annular appearance. We have explored a wide variety of benign and malignant skin tumors and lymphoproliferative diseases forming an annular shape.

Annular Erythemas and Purpuras

Annular dermatoses are a heterogeneous and extremely diverse group of skin diseases, which share in common annular, ring-like patterns with centrifugal spreading. Numerous skin diseases can sometimes display annular lesions, but some specific skin conditions are originally annular. We take the opportunity to review here mainly the causes of primary annular erythemas and their differential diagnoses, but also the rare causes of annular purpuras.

Annular skin tumors and lymphoproliferative diseases

Determining the shape of the skin lesion may provide a diagnostic clue in dermatology practice, more commonly for inflammatory diseases but also for skin tumors. The annular formation may develop by diverse mechanisms in skin tumors. Annular lesions may occur from the onset of the tumor as sparing the central area or depression and/or ulceration in the center of the tumor or outward expansion of the primary lesion. Clustering of multiple papulonodular lesions sparing the central area or relatively independent processes acting on the central and peripheral components of the tumor may also result in an annular appearance. We have explored a wide variety of benign and malignant skin tumors and lymphoproliferative diseases forming an annular shape.

Annular dermatoses with rheumatologic implications

A wide variety of cutaneous disorders present with annular (ringlike) skin lesions, and some of them carry rheumatologic implications because they may involve the joints or belong to the spectrum of connective tissue diseases. The diagnosis of an annular rheumatologic skin disease is possible with a correct clinicopathologic correlation, with a correct anamnesis of the patient, with the evaluation of systemic symptoms, laboratory and instrumental investigations, and finally with a cutaneous biopsy.

Papulosquamous annular diseases

Papulosquamous diseases represent a commonly encountered group of cutaneous disorders in dermatology. Lesions can present with papules and plaques in various configurations, including annular forms. Some of these disorders are expected to appear in annular configurations, such as pityriasis rosea and subcorneal pustular dermatosis. Others may either begin as or even progress to annular configurations, including psoriasis vulgaris, seborrheic dermatitis, and nummular dermatitis. We have reviewed common papulosquamous diseases that can present with annular lesions, which includes psoriasis vulgaris, pityriasis rosea, subcorneal pustular dermatosis, contact dermatitis, seborrheic dermatitis, and nummular dermatitis. For each disorder, we have discussed the details of presentation and differential diseases to be considered.

Tissue-Resident Memory T Cells in Skin Diseases: A Systematic Review

In health, the non-recirculating nature and long-term persistence of tissue-resident memory T cells (TRMs) in tissues protects against invading pathogens. In disease, pathogenic TRMs contribute to the recurring traits of many skin diseases. We aimed to conduct a systematic literature review on the current understanding of the role of TRMs in skin diseases and identify gaps as well as future research paths. EMBASE, PubMed, SCOPUS, Web of Science, Clinicaltrials.gov and WHO Trials Registry were searched systematically for relevant studies from their inception to October 2020. Included studies were reviewed independently by two authors. This study was conducted in accordance with the PRISMA-S guidelines. This protocol was registered with the PROSPERO database (ref: CRD42020206416). We identified 96 studies meeting the inclusion criteria. TRMs have mostly been investigated in murine skin and in relation to infectious skin diseases. Pathogenic TRMs have been characterized in various skin diseases including psoriasis, vitiligo and cutaneous T-cell lymphoma. Studies are needed to discover biomarkers that may delineate TRMs poised for pathogenic activity in skin diseases and establish to which extent TRMs are contingent on the local skin microenvironment. Additionally, future studies may investigate the effects of current treatments on the persistence of pathogenic TRMs in human skin.