Dermatophyte infections mimicking other skin diseases: a 154-person case survey of tinea atypica in the district of Cagliari (Italy)

Tinea Incognito: Challenges in Diagnosis and Management

Tinea incognito is a dermatophyte infection with atypical features, due to the use of topical or systemic steroids or other immunosuppressive medications. Delayed diagnosis, spread of the infection to critical body surfaces, resistance to antifungal drugs, and increased costs due to prolonged hospitalization and multiple treatment regimens often complicate tinea incognito. It can affect individuals of all ages and genders, but it is more common in children. Atypical clinical appearance often necessitates differentiation from other diseases such as eczema, seborrheic dermatitis, lupus erythematosus, psoriasis, or other non-fungal skin conditions. The treatment of tinea incognito usually involves discontinuation of topical steroids or other immunosuppressive medications. Preventive measures and management of the underlying fungal infection are necessary and can be achieved with antifungal drugs. Patients should wear loose cotton clothes, use boiling water for laundry, and iron their clothing before wearing them. Additionally, they should avoid sharing bed linens, towels, clothes, and shoes. This review aims to raise awareness of tinea incognito among health practitioners, provide tips for detecting the disorder, include it in the differentials, and evaluate the available diagnostic procedures.

Tinea Incognito

Tinea incognito (TI), or incognita, are superficial fungal dermatophyte infections that are changed in shape, most frequently because of topical, systemic steroids use and other immunosuppressants. There are different clinical presentations depending on host factors and the species of dermatophyte causing the disorder. Diagnosis can be challenging and might need combined methods. Once diagnosed the treatment is the usual antifungals, either topical or systemic or combined depending on the site, extent, and host factors.

Atypical and Unpredictable Superficial Mycosis Presentations: A Narrative Review

While typically exhibiting characteristic features, fungal infections can sometimes present in an unusual context, having improbable localization (eyelid, face, or joint); mimicking other skin diseases such as eczema, psoriasis, or mycosis fungoides; and appearing with unexpected color, shape, or distribution. The emergence of such a challenging clinical picture is attributed to the complex interplay of host characteristics (hygiene and aging population), environment (climate change), advances in medical procedures, and agent factors (fungal resistance and species emergence). We aim to provide a better understanding of unusual epidemiological contexts and atypical manifestations of fungal superficial diseases, knowing that there is no pre-established clinical guide for these conditions. Thus, a literature examination was performed to provide a comprehensive analysis on rare and atypical superficial mycosis as well as an update on certain fungal clinical manifestations and their significance. The research and standard data extraction were performed using PubMed, Medline, Scopus, and EMBASE databases, and a total of 222 articles were identified. This review covers published research findings for the past six months.

In vitro virulotyping, antifungal susceptibility testing and DNA fingerprinting of Microsporum canis strains of canine and feline origin

Microsporum canis is considered the common dermatophyte agent associated with ringworm in felines and canines. In the present study, we sampled n = 548 felines and canines for the probable isolation of M. canis. The rate of isolation from the cats and dogs was 70.27 % (52/74) and 1.68 % (8/474), respectively and Persian cats were found to be highly susceptible to M. canis infection. The strains were evaluated for their production of phospholipase, lipase, catalase, and hemolysis and their ability to grow at 35 ℃. All the strains were identified as low producers of catalase and n = 17 strains exhibited high thermotolerance ability. Terbinafine was found to be the most effective antifungal drug and fluconazole was the least effective, in vitro. AFLP analysis revealed three genotypes of M. canis with 15 sub-clusters showing ≥ 90 % similarity and 7 sub-clusters exhibiting 100 % similarity. However, the phenotypic characters cannot be attributed based on the AFLP profiles.

Tinea Incognito—A Great Physician Pitfall

Tinea incognito is a dermatophyte infection exacerbated after inadequate administration of topical or systemic glucocorticoids. A 57-year-old man presented to the Department of Dermatology due to skin lesions persisting for one month. He reported having recently worked under hot conditions, in tight clothing, which caused sweating. Later, he noticed erythematous–exfoliative lesions in his groins and on the buttocks. He presented to the general practitioner who diagnosed him with eczema and prescribed clobetasole ointment. Since the skin lesions became more severe, he presented to the Department of Dermatology. On the physical examination, extensive erythematous–infiltrative lesions were observed in the area of medial, lateral, and posterior surface of both thighs and buttocks. Pustules were also present. Suspicion of tinea incognito was raised, and direct mycological examination and culture confirmed the presence of dermatophytes. The patient was prescribed topical terbinafine and oral itraconazole. Tinea incognito may be challenging to diagnose because the clinical presentation is relatively nonspecific and definitive culture or histopathological diagnosis such as by microscopic sample examination to identify fungal elements is not universally available. Every doctor has to keep in mind the fact that tinea may be a great mimicker of other dermatoses and to not prescribe medications without microscopic confirmation of tinea, and refer patients for dermatological consultation in case of doubt.

State-of-the-Art Dermatophyte Infections: Epidemiology Aspects, Pathophysiology, and Resistance Mechanisms

The burden of fungal infections is not widely appreciated. Although these infections are responsible for over one million deaths annually, it is estimated that one billion people are affected by severe fungal diseases. Mycoses of nails and skin, primarily caused by fungi known as dermatophytes, are the most common fungal infections. Trichophyton rubrum appears to be the most common causative agent of dermatophytosis, followed by Trichophyton interdigitale. An estimated 25% of the world’s population suffers from dermatomycosis. Although these infections are not lethal, they compromise the quality of life of infected patients. The outcome of antidermatophytic treatments is impaired by various conditions, such as resistance and tolerance of certain dermatophyte strains. The adage “know your enemy” must be the focus of fungal research. There is an urgent need to increase awareness about the significance of these infections with precise epidemiological data and to improve knowledge regarding fungal biology and pathogenesis, with an emphasis on adaptive mechanisms to tackle adverse conditions from host counteractions. This review outlines the current knowledge about dermatophyte infections, with a focus on signaling pathways required for fungal infection establishment and a broad perspective on cellular and molecular factors involved in antifungal resistance and tolerance.

Bullous Tinea Incognito in a Bulgarian Child: First Description in the Medical Literature!

For the first time in the world medical literature, we describe a rare form of cutaneous dermatophytosis – a bullous form of Tinea incognito, classified by clinical picture, histopathological findings and an isolated infectious agent from the microbiological culture. After a thorough review of Medline/PubMed’s relevant literature, we could not find similar cases of patients with Tinea incognito who are clinically presented with bullous lesions at the same time. Local application of corticosteroids in infants with unknown lesions may lead to progression of the underlying disease and may cause some serious problems in differential diagnosis aspect, while the clinical expression remains completely masked. Exactly for this reason, right at the beginning of the clinical complaints, a skin biopsy should be obligatorily performed in parallel with microbiological swabs. If there is no improvement after the local corticosteroid application, then diagnosis revision and change of the strategy of clinical behaviour would be appropriate to be done. The systemic treatment that we performed with Fluconazole 50 mg in combination with the local antimycotic agent for a 2-week period led to complete remission.

Tinea Incognito — Incorrect Initial Diagnosis. Case Series Presentation with Emphasis on the Mycological Examination

Tinea incognito defines a modified clinical aspect of a tinea following an immunosuppressive therapy, mostly with potent topical steroids. Its diagnosis may be delayed by its delusive appearance, especially in small children and young adults. We present a series of 2 cases of Tinea incognito developed at different ages and incorrectly diagnosed initially, where the clinical diagnosis was followed by mycological examination and positive therapeutic test with antifungal medication, helping to avoid unnecessary laboratory investigations and to prevent further complications.

Advances in Microbiology, Infectious Diseases and Public Health: Refractory Trichophyton rubrum Infections in Turin, Italy: A Problem Still Present

Dermatophytosis caused by Trichophyton rubrum is the most common cutaneous fungal infection in industrialized countries and worldwide with high recurrence and lack of treatment response. In addition, patients with cutaneous and concurrent toenail lesions are often misdiagnosed and therefore treated with an inappropriate therapy. In this study, we evaluated five previously misdiagnosed cases of T.rubrum chronic dermatophytosis sustained by two variants at sites distant from the primary lesion. Our patients were successfully treated by systemic and topical therapy, and 1 year after the end of therapy follow-up did not show any recurrence of infection.Our data indicate that the localization of all lesions, the isolation and the identification of the causative fungus are essential to establish the diagnosis and the setting of a correct therapeutic treatment to avoid recurrences.