Dermatophyte infections

Last reviewed: 24 Aug 2023
Last updated: 08 Nov 2022



History and exam

Key diagnostic factors

  • scaling scalp lesions
  • patchy alopecia
  • erythematous, scaling skin lesions with central clearing
  • erythematous, scaling rash with follicular pustules in beard or mustache
  • erythematous, annular patches on face
  • vesicles and scaling of hands
  • fissuring, maceration, and scaling in the interdigital spaces of the fourth and fifth toes
  • chronically, scaly, hyperkeratotic plantar skin with erythema of the soles, heels, and sides of the feet
  • folliculitis with nodules
More key diagnostic factors

Other diagnostic factors

  • thickened nail with subungual hyperkeratosis, onycholysis, and white-yellow to brown discoloration
  • small, white speckled patches on the surface of the nail plate with crumbling nail
  • lymphadenopathy
  • black-dot alopecia
  • milky white nail plate
  • area of leukonychia in the proximal nail plate
Other diagnostic factors

Risk factors

  • exposure to infected people, animals, or soil
  • exposure to fomites, including hat, combs, hairbrushes, and upholstery
  • chronic topical or oral corticosteroid use
  • HIV
  • diabetes mellitus and other metabolic disorders
  • occlusive clothing
  • hot, humid weather
  • obesity
  • hyperhidrosis
  • frequenting public bathing areas while barefoot
  • deformities of the feet
  • recurrent trauma to the skin
  • contact sports
  • atopic dermatitis
  • positive family history
  • peripheral vascular disease
More risk factors

Diagnostic investigations

1st investigations to order

  • potassium hydroxide (KOH) microscopy
More 1st investigations to order

Investigations to consider

  • dermoscopy
  • fungal culture
  • polymerase chain reaction (PCR)
  • Wood lamp exam (ultraviolet light)
More investigations to consider

Emerging tests

  • reflectance confocal microscopy

Treatment algorithm


tinea capitis

tinea barbae, tinea manuum, or Majocchi granuloma

tinea faciale, tinea corporis, tinea cruris, or tinea pedis

tinea unguium (onychomycosis)



Antonella Tosti, MD

Professor of Clinical Dermatology

Dermatology and Cutaneous Surgery

University of Miami Health System



AT received honorarium and travel reimbursement from Valeant, PharmaDerm, and Polichem, is on the speaker bureau for PharmaDerm, and is a consultant for Erchonia Laser and Almirall.


Dr Antonella Tosti would like to gratefully acknowledge Dr Keira L. Barr and Dr Barry L. Hainer, the previous contributors to this topic.


KLB declares that she has no competing interests. BLH is on the speaker bureaus for the vaccine programs of Merck and Sanofi-Pasteur pharmaceutical companies.

Peer reviewers

Nanette Silverberg, MD

Clinical Professor of Dermatology

Columbia University College of Physicians and Surgeons

New York City



NS declares that she has no competing interests.

Christina M. Gelbard, MD

Department of Dermatology

UT Dermatology

Health Science Center of Houston




CMG declares that she has no competing interests.

  • Dermatophyte infections images
  • Differentials

    • Atopic dermatitis
    • Dyshidrotic dermatitis
    • Lichen simplex chronicus
    More Differentials
  • Guidelines

    • Guidelines for the management of dermatomycosis
    • Antifungal agents for common outpatient paediatric infections
    More Guidelines
  • Patient leaflets

    Athlete's foot

    Ringworm of the body

    More Patient leaflets
  • padlock-lockedLog in or subscribe to access all of BMJ Best Practice

Use of this content is subject to our disclaimer