Year : 2017 | Volume
: 1 | Issue : 3 | Page : 1--2
Mellow to the malicious: Could Trichophyton mentagrophytes be the malefactor?
Manjunath Shenoy Mala
Convener, IADVL Task-force Against Recalcitrant Tinea (ITART); Department of Dermatology, Yenepoya Medical College, Yenepoya University, Mangalore, Karnataka, India
Manjunath Shenoy Mala
Department of Dermatology, Yenepoya Medical College, Yenepoya University, Mangalore - 575 018, Karnataka
|How to cite this article:|
Mala MS. Mellow to the malicious: Could Trichophyton mentagrophytes be the malefactor?.Clin Dermatol Rev 2017;1:1-2
|How to cite this URL:|
Mala MS. Mellow to the malicious: Could Trichophyton mentagrophytes be the malefactor?. Clin Dermatol Rev [serial online] 2017 [cited 2018 Nov 18 ];1:1-2
Available from: http://www.cdriadvlkn.org/text.asp?2017/1/3/1/216273
Dermatophytes are the most common fungal agents causing the superficial skin infections. Superficial mycoses have seldom been a cause of major concern even in hot and humid countries such as India until the last 5 years or so. Currently, dermatophytosis has been a major contributor to the dermatology outpatients. Raise in the recalcitrant and relapsing dermatophytic infections has not been uncommon. Inadequate or no response to the commonly used topical and even systemic anti-fungal agents such as griseofulvin and terbinafine has been frequently noticed. Drugs which are better reserved for systemic mycosis such as itraconazole have been used increasingly. Prolonged treatment beyond the recommended duration has been inevitable. Most of these patients are neither diabetics nor immunocompromised; all of a sudden it is felt like we are fighting a battle with inefficient weapons.
Chronic dermatophytosis can be defined as the persistence of the signs of the disease for >6 months in spite of regular treatment. It was known to occur and has been studied in the past; tinea corporis and tinea cruris were most common accounting for about 10% of all cases. Recent data indicate that there is an increased prevalence of chronic dermatophytosis. Factors responsible for this have not been scientifically studied, and many reasons have been speculated including the fomites, inadequate treatment, failure to treat the contacts, use of topical corticosteroids, and other host-related factors. These cannot adequately explain the onslaught of these infections, and hence, it appears that some agent-related factors exist. Trichophyton rubrum, by the virtue of having several advantages, was the leading cause of dermatophytosis and chronic dermatophytosis. It was the most frequent isolate during the 20th and early 21st century.,
There has been a changing pattern of the dermatophyte isolates in India. Currently, Trichophyton mentagrophytes is the most frequent isolate.,, T. mentagrophytes is distinguished from the historically ubiquitous T. rubrum in that the former may be a zoonotic and is capable of inducing more inflammation. Infection by T. mentagrophytes has been an underestimated cause of highly contagious glabrous skin infection. Human-adapted T. mentagrophytes var. interdigitale frequently isolated from tinea pedis differs clinically and morphologically from animal-associated (zoophilic) one and should be classified as a different fungus. Its status within the anamorphic (conidial) taxonomy is still unsettled. Literature has also been confusing because both teleomorphic and anamorphic nomenclatures of T. mentagrophytes complex have been used. Arthroderma benhamiae, Arthroderma vanbreuseghemii, and Arthroderma simii are the various teleomorphic forms of T. mentagrophytes complex and are reported from various parts of the world. In Germany, there has been an increase in A. benhamiae infections. These pathogen reservoirs of Trichophyton species of A. benhamiae corresponded to the zoophilic T. interdigitale isolates, and the réservoir was the small rodents, mainly guinea pigs.
Identification of the fungal agents can be done based on the colony morphology and slide culture in most institutional and many other laboratories. Further identification of the species requires various molecular biology techniques. In India, it is not done because the facilities are lacking in most institutions. Cutaneous fungal infections are not the thrust area of research in mycology; hence, there is a vast lacuna in understanding the insurgency of the dermatophytosis in India. Whether we are going through a new epidemic? If so, how is it clinically different than the regular dermatophytic infections? What is the ideal therapeutic regimen? Is there any anti-fungal resistance lurking? How far the host-related factors play a role? Many such questions are needed to be answered in the near future. We require to conduct more studies on dermatophytosis. These include isolation of the dermatophytes in cultures, determining their in vitro antifungal susceptibility by traditional methods and complement them with molecular techniques technique for developing accurate diagnostic and appropriate management strategies. Many therapeutic self-styled regimens have been practiced to counter the onslaught of this florid and recurrent dermatophytosis. Practicing dermatologists are facing the most difficult and unexpected situation with no definite answers. It is the duty of the academic dermatologists and mycologists to find the reason and provide with an approved therapeutic guidelines.
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