Case 177. Trichophytosis (tinea capitis) (13 y-o F)
         
    Biopsy from scalp skin showing mild erythema with persistent scaliness and minimal hair loss    
         
   
Key words : 
Trichophyton rubrum, Microsporum canis, tinea capitis, tinea manus, folliculitis, kerion Celci    
     
 
     
Trichophyton tonsurans and T. violaceum cause endothrix-type infection. The fungi invade the hair, entering the hair cortex just above the hair bulb (HE).   The endothrix infection is evident by PAS stain. T. rubrum, the commonest cause of tinea corporis, cannot be a scalp pathogen.
     
 
     
Reference case 177A
Kerion Celci, deeply situated trichophytosis on the scalp, showing suppurative and destructive follicutitis (gross findings). Severe folliculitis and perifolliculitis result in boggy violaceous inflammatory area with suppuration and alopecia.
  Reference case 177A
Kerion Celci, histologically showing perifollicular abscess formation (HE). Pathogens are hardly identified in the lesion. Zoophilic and endothrix fungi, such as Trichophyton verrucosum, T. tonsurans and Microsporum canis, are the causative agents of kerion.
     
 
     
case 177A
Macroconidium of zoophilic Microsporum canis on the culture plate (Cotton blue). An isolate from kerion Celci. Dermatophytes are categorized into three ecological groups. Anthropophilic (affecting human), zoophilic (affecting animals) and geophilic (saprophytes in the soil). Anthropophilic fungi, such as T. rubrum, cause chronic recurrent infection (including athlete's foot), while the latter two cause acute severe infection to human.
  Reference case 177B
Tinea corporis caused by Trichophyton rubrum (gross findings). Small vesicles clustered on the red-colored papule histologically correspond to intraepidermal spongiotic vesiculation.
     
 
     
Reference case 177B
Tinea corporis caused by Trichophyton rubrum. Biopsied specimen (Grocott). Anthropophilic dermatophytes stay in the cornified layer and do not invade the hair follicle, while T. rubrum may show ectothrix-type follicular involvement.
  Reference case 177C
Tinea manus. Interphalangeal skin biopsied from a 74 y-o female (HE). Spongiotic acanthosis, elongation of the rete ridges and chronic dermal inflammation are seen. Mycelia are observed within the hyperkeratotic layer.
     
   
     
Reference case 177C
Tinea manus. Interphalangeal skin biopsied from a 74 y-o female (PAS). Numerous mycelia are clearly identified in the hyperkeratotic layer.