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Superficial mycoses


1. Pityriasis versicolor

  1. Chronic superficial infection of stratum corneum
  2. White to brown colored lesions covered with scales
  3. Caused by lipophilic fungus Malassezia furfur  
  4. Common sites: chest, back, abdomen, neck 

Laboratory diagnosis

  1. Direct Examination: 10% KOH mount of scrapings from the lesion shows yeast cells (2-7μm) along with short curved hyphae (banana & grapes; spaghetti & meat ball appearance)
  2. Culture: On SDA overlaid with olive oil (lipophilic fungus); creamy colonies develop in 5-7 days.  

2. Piedra

  1. Fungal infection of hair, characterized by appearance of firm, irregular nodules along the hair shaft.  

a. Black piedra

  1. Caused by Piedraia hortae
  2. Discrete black, gritty, hard nodules on the hair of the scalp
  3. 10% KOH mount of the crushed nodule reveals dark septate hyphae with club shaped asci, each containing 2-8 ascospores (unique among pathogenic fungi as it produces sexual spores in the parasitic phase) 

b. White piedra

  1. Caused by Trichosporon beigelii
  2. Soft, mucilaginous, grayish nodules on the hair of genital area, beard, moustache
  3. Hair breaks at the point of infection, leaving the distal end of the hair swollen
  4. 10% KOH mount reveals mycelia which fragment into arthrospores.  

3. Tinea nigra

  1. Caused by dematiaceous fungus Exophiala werneckii
  2. Brown to black discoloration of the thickly keratinised sites such as palms and soles.
  3. 10% KOH mount shows brown septate branching hyphae and budding yeast cells (1-5μm). On SDA it forms moist, dark colored colonies. 

4. Dermatophytosis

  1. Dermatophytosis, tinea or ringworm is the most common superficial mycosis
  2. It infects keratinised tissues of the skin, hair & nails.
  3. Caused by 42 species of dermatophytes belonging to three genera:
  • Trichophyton: 24 species (infect skin, hair & nails)
  • Microsporum: 16 species (infect skin & hair)
  • Epidermophyton: 2 species (infect skin & nails)

iv. On the basis of natural habitat they are classified into three groups:

  • Geophilic: found in soil
  • Zoophilic: found in domestic or wild animals
  • Anthropophilic: found exclusively in humans

Examples of dermatophytes




T. ajelloi

T. terrestre

M. gypseum

M. nanum

E. stockdaleae

T. equinum

T.mentagrophytes var. mentagrophytes

T. verrucosum

M. canis


T. mentagrophytes var. intedigitale

T. rubrum

T. schoenlenii

T. tonsurans

T. violaceum

M. audounii

M. ferrugenium

E. floccosum

v. Secondary eruptions may occur in sensitized patients due to circulation of antigen from the primary site. It is called as dermatophytid or id reaction.


Clinically it is classified depending upon the site involved:

Clinical classification

Etiological agent

Tinea corporis

Tinea imbricata (Indian ringworm, hanuman ringworm)

T. rubrum

T. concentricum

Tinea pedis (athlete’s foot)

T. rubrum, T. mentagrophytes

Tinea capitis



Trichophyton spp., Microsporum spp.

T. verrucosum, T. mentagrophytes

T. schoenlenii, T. violaceum, M. gypseum

Tinea cruris (jock itch)

E. floccosum, T. rubrum, T. mentagrophytes

Tinea barbae (barbers itch)

T. rubrum, T. mentagrophytes

Tinea unguium (nail)

T. rubrum, T. mentagrophytes

Tinea manum (hands)

T. rubrum, E. floccosum


vi. Two types of hair invasion are seen with dermatophytes:

  • Ectothrix: arthroconidia appear as sheath on the surface of the hair shaft.
  • Endothrix: arthrospores formation occurs occurs entirely within the hair completely filling the hair shaft.



T. mentagrophytes

T. rubrum

T. verrucosum

M. canis

M. gypseum

M. audouinii

T. schoenlenii

T. tonsurans

T. violaceum


  1. Laboratory diagnosis:
  • KOH wet mount: branching hyaline mycelium, arthrospores formation.
  • Culture: grow on SDA. Septate hyaline hyphae, microconidia and macroconidia. The differentiation of three genera based on the nature of macroconidia.

Characteristics of dermatophyte macroconidia




No. of septations

Thickness of wall

Surface of wall

Manner of attachment


Boat shaped







Pencil shaped







Club shaped





Groups of



Test to differentiate T. mentagrophytes from T. rubrum

  1. T mentagrophytes urease +ve
  2. T rubrum produce deep red pigment on corn meal agar
  3. In vitro hair perforation test positive with T. mentagrophytes

b. Hair perforation test:

  1. Filter paper soaked in distilled water
  2. Sterilized prepubertal / infant hair
  3. Inoculate the hair, incubate for four weeks at 25°C
  4. Wet mount: conical perforation of the hair shaft
  5. T. mentagrophytes & M. canis (+); T. rubrum & M. equinum (-) 

c. Urease test:

  1. Christensen’s urea agar inoculated
  2. Incubated at room temperature for 5 days
  3. T. mentagrophytes (+) & T. rubrum (-)

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