In the past decade, an epidemic of severe antimicrobial-resistant tinea has emerged in certain South Asian and Middle Eastern countries.[1,2] This is thought to be because of inappropriate use and overuse of topical antifungals and corticosteroids.[3,4,5] Antimicrobial-resistant tinea infections are frequently caused by the novel dermatophyte species Trichophyton indotineae (formerly known as Trichophyton mentagrophytes ITS genotype VIII).[6,7]T indotineae infections are characterized by widespread inflamed or dry and scaly pruritic plaques of tinea corporis, cruris, or faciei.[4,8]
Recently, T indotineae infections have been reported in the United States. Infections have also been reported in Europe and Canada.[1] Topical antifungals and oral terbinafine are frequently ineffective against T indotineae infections. Other oral antifungal drugs, including fluconazole, griseofulvin, and ketoconazole are also frequently ineffective.[9] Antimicrobial-resistant tinea caused by the dermatophyte Trichophyton rubrum and azole-resistant dermatophytes are also growing public health concerns.[10,11]
Here are five things to know about antimicrobial-resistant tinea:
1) Be on the lookout for antimicrobial-resistant tinea.
Healthcare providers should consider T indotineae infection in patients with widespread tinea, particularly when lesions do not improve with first-line topical antifungal agents or oral terbinafine. The lesions of T indotineae infection are often widespread annular scaly plaques that are highly pruritic and inflamed. Healthcare providers should ask their patients about travel history. In Europe and North America, most (but not all) patients with T indotineae infection have reported recent travel to countries in South Asia (eg, India, Bangladesh) or the Middle East (eg, Iran, Iraq, United Arab Emirates).[8]
2) Diagnosing T indotineae requires specialized testing.
Diagnosing T indotineae infection can be challenging because the organism resembles T mentagrophytes and T intergitale[12] in culture. Correct identification requires genomic sequencing, which is available at select public health, academic, and commercial laboratories. Healthcare providers who suspect antimicrobial-resistant tinea can contact their state or local health departments for assistance. Public health officials who are concerned about potential cases of drug-resistant tinea infections can email fungaloutbreaks@cdc.gov for assistance with recommendations and testing.
3) Be aware of treatment options and challenges for patients with drug-resistant tinea.
Many T indotineae infections do not resolve with oral terbinafine therapy. Itraconazole is generally the drug of choice, but patients frequently require a prolonged course of therapy, usually 4-8 weeks and up to 12 weeks in certain instances.[1,7] When prescribing itraconazole, healthcare providers should be aware of its potential for drug-drug interactions, side effects, and challenges with drug absorption. Therapeutic drug monitoring for serum levels of itraconazole might help ensure adequate levels while preventing drug toxicity.
Of note, itraconazole-resistant T indotineae infections have been reported. Voriconazole and posaconazole, antifungals that are usually reserved for invasive fungal infections, might play a role in treating multidrug-resistant T indotineae infections.[13] Efinaconazole, a newer topical azole, has demonstrated high in vitro activity against dermatophytes with elevated minimum inhibitory concentration values against terbinafine; this drug might have a role in treating terbinafine-resistant dermatophyte infections, but additional research is needed.[14] Consultation with a dermatologist or infectious disease specialist can help with guiding antifungal therapy choice, serum drug level monitoring, and treatment duration.
4) Appropriate diagnosis and patient education can help speed treatment and stop the spread of T indotineae
Many products for treating skin rashes, including antifungal and corticosteroids creams, can be purchased over the counter. Although corticosteroid creams might initially improve tinea symptoms such as scale or itch, these creams do not kill the fungus causing tinea, can ultimately worsen the patient's condition, and may obscure or delay the correct diagnosis.[15,16] For patients with a suspected tinea infection of the skin, obtaining a diagnosis from a healthcare professional might help minimize inappropriate antifungal and corticosteroid use, leading to improved patient outcomes.[2]
It is important for patients self-treating with over-the-counter antifungal medications to follow label instructions. Patients should use prescription antifungal medications according to their healthcare provider's instructions. Healthcare providers should take Standard Precautions when caring for patients with possible tinea and can educate patients on ways to prevent tinea, which can be found on the Centers for Disease Control and Prevention website.
5) Be a steward of antifungal medications and corticosteroids.
Healthcare providers can help prevent the spread of drug-resistant tinea by being stewards of antifungal medications and corticosteroids. Certain common skin conditions, such as psoriasis, can resemble superficial fungal infections but should not be treated with antifungals. Diagnostic testing (eg, direct microscopy, culture, polymerase chain reaction) can help establish or rule out a fungal diagnosis and ensure that patients receive appropriate therapy.
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COMMENTARY
5 Things to Know About Antimicrobial-Resistant Tinea (Ringworm)
Jeremy A. W. Gold, MD, MS; Shyam B. Verma, MBBS, DVD, PhD; Shawn R. Lockhart, PhD; Pietro Nenoff, MD; Silke Uhrlaß; Dallas J. Smith, PharmD; Avrom S. Caplan, MD
DisclosuresMay 12, 2023
Editorial Collaboration
Medscape &
In the past decade, an epidemic of severe antimicrobial-resistant tinea has emerged in certain South Asian and Middle Eastern countries.[1,2] This is thought to be because of inappropriate use and overuse of topical antifungals and corticosteroids.[3,4,5] Antimicrobial-resistant tinea infections are frequently caused by the novel dermatophyte species Trichophyton indotineae (formerly known as Trichophyton mentagrophytes ITS genotype VIII).[6,7]T indotineae infections are characterized by widespread inflamed or dry and scaly pruritic plaques of tinea corporis, cruris, or faciei.[4,8]
Recently, T indotineae infections have been reported in the United States. Infections have also been reported in Europe and Canada.[1] Topical antifungals and oral terbinafine are frequently ineffective against T indotineae infections. Other oral antifungal drugs, including fluconazole, griseofulvin, and ketoconazole are also frequently ineffective.[9] Antimicrobial-resistant tinea caused by the dermatophyte Trichophyton rubrum and azole-resistant dermatophytes are also growing public health concerns.[10,11]
Here are five things to know about antimicrobial-resistant tinea:
1) Be on the lookout for antimicrobial-resistant tinea.
Healthcare providers should consider T indotineae infection in patients with widespread tinea, particularly when lesions do not improve with first-line topical antifungal agents or oral terbinafine. The lesions of T indotineae infection are often widespread annular scaly plaques that are highly pruritic and inflamed. Healthcare providers should ask their patients about travel history. In Europe and North America, most (but not all) patients with T indotineae infection have reported recent travel to countries in South Asia (eg, India, Bangladesh) or the Middle East (eg, Iran, Iraq, United Arab Emirates).[8]
2) Diagnosing T indotineae requires specialized testing.
Diagnosing T indotineae infection can be challenging because the organism resembles T mentagrophytes and T intergitale[12] in culture. Correct identification requires genomic sequencing, which is available at select public health, academic, and commercial laboratories. Healthcare providers who suspect antimicrobial-resistant tinea can contact their state or local health departments for assistance. Public health officials who are concerned about potential cases of drug-resistant tinea infections can email fungaloutbreaks@cdc.gov for assistance with recommendations and testing.
3) Be aware of treatment options and challenges for patients with drug-resistant tinea.
Many T indotineae infections do not resolve with oral terbinafine therapy. Itraconazole is generally the drug of choice, but patients frequently require a prolonged course of therapy, usually 4-8 weeks and up to 12 weeks in certain instances.[1,7] When prescribing itraconazole, healthcare providers should be aware of its potential for drug-drug interactions, side effects, and challenges with drug absorption. Therapeutic drug monitoring for serum levels of itraconazole might help ensure adequate levels while preventing drug toxicity.
Of note, itraconazole-resistant T indotineae infections have been reported. Voriconazole and posaconazole, antifungals that are usually reserved for invasive fungal infections, might play a role in treating multidrug-resistant T indotineae infections.[13] Efinaconazole, a newer topical azole, has demonstrated high in vitro activity against dermatophytes with elevated minimum inhibitory concentration values against terbinafine; this drug might have a role in treating terbinafine-resistant dermatophyte infections, but additional research is needed.[14] Consultation with a dermatologist or infectious disease specialist can help with guiding antifungal therapy choice, serum drug level monitoring, and treatment duration.
4) Appropriate diagnosis and patient education can help speed treatment and stop the spread of T indotineae
Many products for treating skin rashes, including antifungal and corticosteroids creams, can be purchased over the counter. Although corticosteroid creams might initially improve tinea symptoms such as scale or itch, these creams do not kill the fungus causing tinea, can ultimately worsen the patient's condition, and may obscure or delay the correct diagnosis.[15,16] For patients with a suspected tinea infection of the skin, obtaining a diagnosis from a healthcare professional might help minimize inappropriate antifungal and corticosteroid use, leading to improved patient outcomes.[2]
It is important for patients self-treating with over-the-counter antifungal medications to follow label instructions. Patients should use prescription antifungal medications according to their healthcare provider's instructions. Healthcare providers should take Standard Precautions when caring for patients with possible tinea and can educate patients on ways to prevent tinea, which can be found on the Centers for Disease Control and Prevention website.
5) Be a steward of antifungal medications and corticosteroids.
Healthcare providers can help prevent the spread of drug-resistant tinea by being stewards of antifungal medications and corticosteroids. Certain common skin conditions, such as psoriasis, can resemble superficial fungal infections but should not be treated with antifungals. Diagnostic testing (eg, direct microscopy, culture, polymerase chain reaction) can help establish or rule out a fungal diagnosis and ensure that patients receive appropriate therapy.
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Cite this: 5 Things to Know About Antimicrobial-Resistant Tinea (Ringworm) - Medscape - May 12, 2023.
Tables
References
Authors and Disclosures
Authors and Disclosures
Authors
Jeremy A. W. Gold, MD, MS
Medical Officer, Mycotic Diseases Branch, Centers for Disease Control and Prevention Atlanta, Georgia
Disclosure: Jeremy A. W. Gold, MD, MS, has disclosed no relevant financial relationships.
Shyam B. Verma, MBBS, DVD, PhD
Nirvana Skin Clinic, Vadodara, Gujarat, India
Disclosure: Shyam B. Verma, MBBS, DVD, PhD, has disclosed no relevant financial relationships.
Shawn R. Lockhart, PhD
Senior Clinical Laboratory Advisor, Mycotic Diseases Branch, Centers for Disease Control and Prevention Atlanta, Georgia
Disclosure: Shawn R. Lockhart, PhD, has disclosed no relevant financial relationships.
Pietro Nenoff, MD
Labopart – Medical Laboratories, Leipzig-Mölbis, Germany
Disclosure: Pietro Nenoff, MD, has disclosed no relevant financial relationships.
Silke Uhrlaß
Labopart – Medical Laboratories, Leipzig-Mölbis, Germany
Disclosure: Silke Uhrlaß has disclosed no relevant financial relationships.
Dallas J. Smith, PharmD
Epidemiologist, Mycotic Diseases Branch Centers for Disease Control and Prevention Atlanta, Georgia
Disclosure: Dallas J. Smith, PharmaD, has disclosed no relevant financial relationships.
Avrom S. Caplan, MD
The Ronald O. Perelman Department of Dermatology, NYU Grossman School of Medicine, New York, NY
Disclosure: Avrom S. Caplan, MD, has disclosed no relevant financial relationships.