Last reviewed: 19 Sep 2021
Last updated: 23 Nov 2020



History and exam

Key diagnostic factors

  • history of skin, hair, or nail lesion
  • skin discomfort
  • 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
  • diffusely dry palmar surface with hyperkeratosis
  • vesicles and scaling of hands
  • erythematous, scaling lesions with raised border on thighs, together with pustules, vesicles, and maceration
  • vesicles, pustules with or without bullae on the soles
  • 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

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
  • absence of distal pulses
  • black-dot alopecia
  • milky white nail plate
  • area of leukonychia in the proximal nail plate

Risk factors

  • exposure to infected people, animals, or soil
  • exposure to fomites, including hat, combs, hairbrushes, and upholstery
  • wrestling
  • 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
  • atopic dermatitis
  • positive family history
  • peripheral vascular disease

Diagnostic investigations

Investigations to consider

  • Wood lamp exam (ultraviolet light) 
  • dermoscopy (trichoscopy)
  • fungal culture
  • polymerase chain reaction (PCR)
  • nail clipping

Emerging tests

  • reflectance confocal microscopy

Treatment algorithm



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, and is on the speaker bureau for PharmaDerm.


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.

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