eMedicine Specialties > Dermatology > Fungal Infections

Tinea Corporis: Differential Diagnoses & Workup

Author: Mary Elizabeth Rushing Lott, MD, Senior Resident, Department of Pediatrics, Miami Children's Hospital
Coauthor(s): Gwendolyn Zember, MD, Consulting Staff, Department of Internal Medicine, University Hospital; Jack L Lesher Jr, MD, Chief, Professor, Department of Internal Medicine, Section of Dermatology, Medical College of Georgia
Contributor Information and Disclosures

Updated: Jun 5, 2008

Differential Diagnoses

Atopic Dermatitis
Nummular Dermatitis
Candidiasis, Cutaneous
Parapsoriasis
Erythema Annulare Centrifugum
Pityriasis Rosea
Erythema Multiforme
Psoriasis, Annular
Erythrasma
Psoriasis, Plaque
Granuloma Annulare
Seborrheic Dermatitis
Granuloma Faciale
Syphilis
Impetigo
Tinea Versicolor
Lupus Erythematosus, Subacute Cutaneous
Lymphocytic Skin Infiltration

Workup

Laboratory Studies

  • A potassium hydroxide (KOH) examination of skin scrapings may be diagnostic.  
    • A KOH test is a microscopic preparation used to visualize fungal elements removed from the skin's stratum corneum.
    • The sample should be taken from the active border of a lesion because this region provides the highest yield of fungal elements. A KOH preparation from a vesicular lesion should be made from the roof of the vesicle.
    • The KOH helps dissolve the keratin and leaves fungal elements intact, revealing numerous septate, branching hyphae amongst epithelial cells.
    • A counterstain, such as chlorazol black E or Parker blue-black ink, may help visualize hyphae under the microscope.
  • A fungal culture is often used as an adjunct to KOH for diagnosis. Fungal culture is more specific than KOH for detecting a dermatophyte infection; therefore, if the clinical suspicion is high yet the KOH result is negative, a fungal culture should be obtained.
  • A few culture mediums are available for dermatophyte growth.  
    • Sabouraud agar containing neopeptone or polypeptone agar and glucose is often used for fungal culture. However, it does not contain antibiotics and may allow overgrowth of fungal and bacterial contaminants.
    • Mycosel, a commonly used agar, is similar to Sabouraud agar but has antibiotics.
    • Commonly, dermatophyte test medium (DTM) is used. It contains antibacterial (ie, gentamicin, chlortetracycline) and antifungal (ie, cycloheximide) solutions in a nutrient agar base. This combination isolates dermatophytes while suppressing other fungal and bacterial species that may contaminate the culture.
  • Following culture inoculation, potential fungal growth is monitored for 2 weeks.
  • Positive culture results vary depending on the medium used.  
    • DTM contains phenol red solution, which causes a color change from straw-yellow to bright-red under alkaline conditions, indicating a positive dermatophyte culture result. However, the color makes identification of culture morphology (particularly pigmentation) difficult.
    • Sabouraud or Mycosel agar should be used to assess gross and microscopic colony characteristics.
  • If the above clinical evaluations are inconclusive, the molecular method of polymerase chain reaction for fungal DNA identification can be applied.7  
  • For atypical presentations, further evaluation for HIV infection and/or an immunocompromised state should be considered.

Histologic Findings

A skin biopsy with a hematoxylin and eosin staining of tinea corporis demonstrates spongiosis, parakeratosis, and a superficial inflammatory infiltrate. Neutrophils may be seen in the stratum corneum, which is a significant diagnostic clue. On occasion, septate branching hyphae are seen in the stratum corneum with hematoxylin and eosin stain, but special fungal stains (eg, periodic acid-Schiff, Gomori methenamine silver) may be required.

More on Tinea Corporis

Overview: Tinea Corporis
Differential Diagnoses & Workup: Tinea Corporis
Treatment & Medication: Tinea Corporis
Follow-up: Tinea Corporis
Multimedia: Tinea Corporis
References
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References

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  2. Sun PL, Ho HT. Concentric rings: an unusual presentation of tinea corporis caused by Microsporum gypseum. Mycoses. Mar 2006;49(2):150-1. [Medline].

  3. Sánchez-Castellanos ME, Mayorga-Rodríguez JA, Sandoval-Tress C, Hernández-Torres M. Tinea incognito due to Trichophyton mentagrophytes. Mycoses. Jan 2007;50(1):85-7. [Medline].

  4. Kim HS, Cho BK, Oh ST. A case of tinea corporis purpurica. Mycoses. Jul 2007;50(4):314-6. [Medline].

  5. Shiraki Y, Hiruma M, Matsuba Y, Kano R, Makimura K, Ikeda S, et al. A case of tinea corporis caused by Arthroderma benhamiae (teleomorph of Tinea mentagrophytes) in a pet shop employee. J Am Acad Dermatol. Jul 2006;55(1):153-4. [Medline].

  6. Placzek M, van den Heuvel ME, Flaig MJ, Korting HC. Perniosis-like tinea corporis caused by Trichophyton verrucosum in cold-exposed individuals. Mycoses. Nov 2006;49(6):476-9. [Medline].

  7. Seyfarth F, Ziemer M, Gräser Y, Elsner P, Hipler UC. Widespread tinea corporis caused by Trichophyton rubrum with non-typical cultural characteristics--diagnosis via PCR. Mycoses. 2007;50 Suppl 2:26-30. [Medline].

  8. Liebel F, Lyte P, Garay M, Babad J, Southall MD. Anti-inflammatory and anti-itch activity of sertaconazole nitrate. Arch Dermatol Res. Sep 2006;298(4):191-9. [Medline].

  9. Leyden J. Pharmacokinetics and pharmacology of terbinafine and itraconazole. J Am Acad Dermatol. May 1998;38(5 Pt 3):S42-7. [Medline].

  10. da Silva Barros ME, de Assis Santos D, Soares Hamdan J. Antifungal susceptibility testing of Trichophyton rubrum by E-test. Arch Dermatol Res. May 2007;299(2):107-9. [Medline].

  11. Wingfield AB, Fernandez-Obregon AC, Wignall FS, Greer DL. Treatment of tinea imbricata: a randomized clinical trial using griseofulvin, terbinafine, itraconazole and fluconazole. Br J Dermatol. Jan 2004;150(1):119-26. [Medline].

  12. Aly R. Ecology and epidemiology of dermatophyte infections. J Am Acad Dermatol. Sep 1994;31(3 Pt 2):S21-5. [Medline].

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  14. Del Rosso JQ, Draelos ZD, Jorizzo JL, Joseph WS, Ribotsky BM, Rich P. Modern methods to treat superficial fungal disease. Cutis. Feb 2007;79(2 Suppl):6-29. [Medline].

  15. Drake LA, Dinehart SM, Farmer ER, Goltz RW, Graham GF, Hardinsky MK, et al. Guidelines of care for superficial mycotic infections of the skin: tinea corporis, tinea cruris, tinea faciei, tinea manuum, and tinea pedis. Guidelines/Outcomes Committee. American Academy of Dermatology. J Am Acad Dermatol. Feb 1996;34(2 Pt 1):282-6. [Medline].

  16. Foster KW, Ghannoum MA, Elewski BE. Epidemiologic surveillance of cutaneous fungal infection in the United States from 1999 to 2002. J Am Acad Dermatol. May 2004;50(5):748-52. [Medline].

  17. Gupta AK, Einarson TR, Summerbell RC, Shear NH. An overview of topical antifungal therapy in dermatomycoses. A North American perspective. Drugs. May 1998;55(5):645-74. [Medline].

  18. Jones HE. Immune response and host resistance of humans to dermatophyte infection. J Am Acad Dermatol. May 1993;28(5 Pt 1):S12-S18. [Medline].

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  20. Lesher JL Jr. Oral therapy of common superficial fungal infections of the skin. J Am Acad Dermatol. Jun 1999;40(6 Pt 2):S31-4. [Medline].

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  24. Theos A. Diagnosis and management of superficial cutaneous fungal infections in children. Pediatr Ann. Jan 2007;36(1):46-54. [Medline].

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Further Reading

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Keywords

ringworm, dermatophyte infection, Trichophyton species, Microsporum species, Epidermophyton species, Trichophyton rubrum, T rubrum, Microsporum canis, M canis, Trichophyton mentagrophytes, T mentagrophytes, Trichophyton tonsurans, T tonsurans, Trichophyton concentricum, T concentricum, Majocchi granuloma, Majocchi's granuloma, tinea imbricata, tinea capitis

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Contributor Information and Disclosures

Author

Mary Elizabeth Rushing Lott, MD, Senior Resident, Department of Pediatrics, Miami Children's Hospital
Mary Elizabeth Rushing Lott, MD is a member of the following medical societies: Alpha Omega Alpha, American Medical Association, and American Medical Student Association/Foundation
Disclosure: Nothing to disclose.

Coauthor(s)

Gwendolyn Zember, MD, Consulting Staff, Department of Internal Medicine, University Hospital
Disclosure: Nothing to disclose.

Jack L Lesher Jr, MD, Chief, Professor, Department of Internal Medicine, Section of Dermatology, Medical College of Georgia
Jack L Lesher Jr, MD is a member of the following medical societies: American Academy of Dermatology, American Dermatological Association, American Medical Association, American Society for Dermatologic Surgery, Medical Association of Georgia, Society for Investigative Dermatology, and Southern Medical Association
Disclosure: Nothing to disclose.

Medical Editor

Janet Fairley, MD, Professor and Head, Department of Dermatology, University of Iowa
Janet Fairley, MD is a member of the following medical societies: American Academy of Dermatology, American Dermatological Association, American Federation for Medical Research, and Society for Investigative Dermatology
Disclosure: Nothing to disclose.

Pharmacy Editor

Richard P Vinson, MD, Assistant Clinical Professor, Department of Dermatology, Texas Tech University School of Medicine; Consulting Staff, Mountain View Dermatology, PA
Richard P Vinson, MD is a member of the following medical societies: American Academy of Dermatology, Association of Military Dermatologists, Texas Dermatological Society, and Texas Medical Association
Disclosure: Nothing to disclose.

Managing Editor

Rosalie Elenitsas, MD, Associate Professor of Dermatology, University of Pennsylvania School of Medicine; Director, Penn Cutaneous Pathology Services, Department of Dermatology, University of Pennsylvania Health System
Rosalie Elenitsas, MD is a member of the following medical societies: American Society of Dermatopathology
Disclosure: Nothing to disclose.

CME Editor

Joel M Gelfand, MD, MSCE, Medical Director, Clinical Studies Unit, Assistant Professor, Department of Dermatology, Associate Scholar, Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania
Joel M Gelfand, MD, MSCE is a member of the following medical societies: Society for Investigative Dermatology
Disclosure: AMGEN Consulting fee Consulting; AMGEN Grant/research funds None; Genentech Consulting fee Consulting; Centocor Consulting fee Consulting; Centocor Grant/research funds None; Covance Consulting fee Consulting; Shire  Consulting

Chief Editor

Dirk M Elston, MD, Director, Department of Dermatology, Geisinger Medical Center
Dirk M Elston, MD is a member of the following medical societies: American Academy of Dermatology
Disclosure: Nothing to disclose.

 
 
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