Superficial Fungal Infections

Question 1

Tinea capitis

Answer 1

Anthropophilic species predominate

Common species -
T. tonsurans (endothrix, Anthropophilic) - African/Caribbean hair type
T. violaceum (endothrix, Anthropophilic)
M. canis (ectothrix, zoophilic)
T. schoenleinii (favus, Anthropophilic)

Associations - AIDS

Endothrix (hyphae within hair shaft —> fragile —> breaks close to hair shaft —> black dots/broken hairs), non-fluorescent under Wood’s lamp “TV inside” -
T. tonsurans (Anthropophilic)
T. violaceum (Anthropophilic)
T. soudanense (African T. rubrum complex, Anthropophilic)
T. yaoundei (African T. rubrum complex, Anthropophilic)
T. gourvilii (African T. rubrum complex, Anthropophilic)
T. rubrum (Anthropophilic) - rare

Ectothrix (hyphae invades mid follicle —> grow inwards towards bulb —> hyphae burst out and grow over surface of hair shaft), brilliant green fluorescence under Wood’s lamp “cat & dog fight outside” -
M. canis (zoophilic) - cat/dog
M. equinum (zoophilic) - horse
M. gypseum (geophilic)
M. audouinii (Anthropophilic)
M. ferrugineum (Anthropophilic)

Favus (septate hyphae with air spaces in hair shaft) greenish grey/white blue fluorescence -
T. schoenleinii (Anthropophilic)
Yellowish cup shaped crusts containing hyphae and keratin debris (scutula)
Most less distinct signs, esp early cases - perifollicular redness, matting of hair

Clinical features -
Itching variable
Partial hair loss with some inflammation

Clinical variants - 
Endothrix -
Non-inflammatory patchy alopecia 
Black dots 
Minimal scale
Gray patch (scaling with patchy hair loss) vs black dot vs diffuse alopecia
Sometimes low grade folliculitis
Sometimes kerion
May have nail involvement/facial lesions 
Anthropophilic species

Ectothrix -
Minimally inflammatory patchy alopecia (more inflammatory in M. canis infection d/t zoophilic species)
Dull grey broken hairs
Fine scaling
Zoophilic, geophilic, Anthropophilic species

Kerion -
Painful inflammatory mass
Pus discharge
Sinus
Thick crusting
Lymphadenopathy
Possible bacterial co-infection —> swab MCS
Zoophilic species - T. mentagrophytes, T. verrucosum
Geophilic species
Anthropophilic species smouldering for weeks, suddenly becoming inflammatory if high hypersensitivity

Favus

DDx - 
AA +/- Seb derm
Trichotillomania
Pityriasis amiantacea
Impetigo secondary to pediculosis
DLE
LPP

Management -
General -
Topical only as adjunct to oral Rx I.el ketoconaxole/selenium sulphide shampoo to prevent spread in early phase of oral Rx
Remove crusts using wet compress for kerion
Treat any co-existing bacterial infection if confirmed by swab MCS
Analgesia for kerion as needed

First line -
Terbinafine daily 4 weeks - 62.5mg < 10kg, 125mg 10-20kg, 250mg > 20kg —> Trichophyton species
Itraconazole 2-4mg/kg/d 4-6 weeks
Griseofulvin 10mg/kg 6 weeks (20mg/kg T. tonsurans, T. schoenleinii for possible longer course) —> Microsporum species

Second line -
Itraconazole 5mg/kg weekly pulse for 2-3 rounds