MC 3 - Fungal Morphology

• Fungal infections

  Also known as "mycoses"

  
• Mycoses


  Caused by certain yeasts, moulds, and dimorphic fungi
• How fungi can cause disease

  • Replication of the fungus (tissue invasion and functional disruption)
  • Immune response
  • Competitive metabolism (consumption of energy and nutrients intended for the host)
  • Toxic metabolites (ex: Candida spp produces acetaldehyde – a carcinogenic substance)
• Superficial mycoses


  Fungal infections of the outermost areas of the human body, including the outer surfaces of hair shafts and the outermost, nonliving layer of the skin

  
• Otomycosis


  A fungal infection in the outer ear, causing pain, itching, ringing, feeling of fullness, discharge, and hearing problems. Common fungi include Aspergillus species and rarely Candida.
• Otomycosis


  • Common in tropical and warm regions
  • Prevention: avoid getting water in ears, dry ears after showering, avoid cotton swabs, avoid scratching, use acetic acid ear drops
• Black piedra


  A fungal infection of the hair shafts, also known as "Trichomycosis nodosa". Caused by Piedraia hortae, commonly seen in people with long hair and excessive use of hair oils.
• Black piedra is asymptomatic, with firmly attached brown-black nodules (<1mm) along the hair shaft that are gritty on palpation.
• White piedra


  An asymptomatic superficial mycosis that affects the hair stems, forming whitish nodules caused by various Trichosporon species. Can spread through contact with contaminated water, soil, plants, or animals.
• Tinea versicolor


  A common fungal infection of the skin that interferes with normal pigmentation, resulting in discolored patches, usually on the trunk and shoulders. Caused by Malassezia furfur.

  
• Tinea versicolor signs and symptoms include patches of skin discoloration, mild itching, and scaling.

  
• Tinea nigra


  An uncommon superficial dermatomycosis usually caused by Hortaea werneckii, presenting as persistent brown or black patches on the palms or soles.
• Tinea nigra patches are slightly scaly and do not itch or sting, slowly enlarging over time.
• Dermatomycoses


  Fungal infections of the living layers of skin (dermis), hair shafts, and nails, commonly caused by dermatophyte fungi of the Trichophyton, Microsporum, and Epidermophyton genera.

  
• Tinea pedis


  Also known as "Athlete's foot", a contagious fungal infection of the feet commonly caused by Trichophyton rubrum, resulting in an itchy, scaly rash.

  
• Tinea pedis


  • Occurs in people with sweaty, confined feet
  • Common signs and symptoms include scaly, peeling or cracked skin between the toes, itchiness, inflamed skin, burning or stinging, blisters, and dry, scaly skin on the bottom of the foot.

  
• Prevention of tinea pedis

  • Let feet air out, wash feet daily, change socks regularly, alternate pairs of shoes, protect feet in public places, be aware of risk factors for spreading
• Tinea corporis


  Ringworm of the body, a rash caused by a fungal infection, usually an itchy, circular rash with clearer skin in the middle. Predominantly caused by Trichophyton and Microsporum dermatophytes.

  
• Clinical variants of tinea corporis

  • Kerion
  • Tinea gladiatorum
  • Tinea imbricata
  • Tinea incognita
  • Majocchi granuloma
  • Bullous tinea corporis
• Tinea capitis


  A disease caused by superficial fungal infection of the scalp, eyebrows, and eyelashes, usually causing itchy, scaly, bald patches on the head.
• Ways tinea capitis can spread

  • Human to human
  • Animal to human
  • Object to human
• Steps to reduce risk of tinea capitis

  • Educate yourself and others
  • Shampoo regularly
  • Keep skin clean and dry
  • Avoid infected animals
  • Avoid sharing personal items
• Tinea cruris


  Also known as "jock itch", a fungal infection that causes a red and itchy rash in warm and moist areas of the body, often in the groin and inner thighs. Commonly caused by Trichophyton rubrum and Epidermophyton floccosum.
• Risk factors for tinea cruris

  • Being male
  • Being a teen or young adult
  • Wearing tight underwear
  • Being overweight
  • Sweating heavily
  • Having a weakened immune system
  • Having diabetes
• Prevention of tinea cruris

  • Stay dry
  • Wear clean clothes
  • Find the correct fit
  • Don't share personal items
  • Treat or prevent athlete's foot

  
• Tinea unguium


  Also known as onychomycosis, a fungal infection of the toenails or fingernails that may involve the matrix, bed, or plate. Most often due to Trichophyton rubrum and T. interdigitale.

  
• Patterns of tinea unguium

  • Lateral onychomycosis
  • Subungual hyperkeratosis
  • Distal onycholysis
  • Superficial white onychomycosis
  • Proximal onychomycosis
  • Complete destruction of the nail
• Subcutaneous mycoses


  Fungal infections of the dermis and underlying tissues, more severe than superficial and cutaneous mycoses, resulting from traumatic implantation of the mould through the dermis.

  
• Sporotrichosis


  A subcutaneous mycosis
• Tinea unguium


  Fungal infection of the toenails or fingernails that may involve any component of the nail unit, including the matrix, bed, or plate

  
• Trichophyton rubrum and T. interdigitale

  Most common causes of tinea unguium
• Patterns of tinea unguium

  • Lateral onychomycosis
  • Subungual hyperkeratosis
  • Distal onycholysis
  • Superficial white onychomycosis
  • Proximal onychomycosis
  • Complete destruction of the nail
• Subcutaneous mycoses


  Fungal infections of the dermis and underlying tissues, more severe than superficial and cutaneous mycoses

  
• Sporotrichosis


  Infection caused by the fungus Sporothrix schenckii, usually after touching contaminated plant matter
• Types of sporotrichosis


  • Cutaneous (skin) sporotrichosis
  • Pulmonary (lung) sporotrichosis
  • Disseminated sporotrichosis

  
• Phaeohyphomycosis


  Infections due to a group of heterogenous organisms called "dematiaceous" or "melanized" fungi, distinguished by melanin in their cell walls
• Systemic mycoses


  Fungal infections of internal organs, sometimes affecting two or more organ systems simultaneously, usually from inhalation of spores or conidia
• Types of aspergillosis


  • Allergic bronchopulmonary aspergillosis (ABPA)
  • Allergic Aspergillus sinusitis
  • Azole-Resistant Aspergillus fumigatus
  • Aspergilloma
  • Chronic pulmonary aspergillosis
  • Invasive aspergillosis
  • Cutaneous (skin) aspergillosis
• Coccidioidomycosis


  Pulmonary or hematogenously spread disseminated disease caused by the fungi Coccidioides immitis and C. posadasii
• Manifestations of coccidioidomycosis


  • Primary coccidioidomycosis
  • Progressive coccidioidomycosis