Derm Micro

  1. Malassezia furfur
    • Normal skin flora
    • common in individuals who work outside and sweat a lot (hot, humid weather)
    • Causes pityriasis or tinea versicolor. Superficial infection of keratinized cells. Degradation of lipids produces acids that damage melanocytes and cause hypopigmented and/or hyperpigmented patches on the chest and back.
    • Diagnosis: KOH mount looks like spaghetti and meatball; coppery/orange fluorescence under woods lamp (UV)
    • Rx: topical miconazole, selenium sulfide (selsun)
  2. Dermatophytes= tinea (ringworms)
    • Filamentous fungi (monomorphic) infect only skin and hair or nails
    • Trichophyton: infects skin, hair, nails
    • Microsporum: infects skin, hair
    • Epidermophyton: infects skin, nails
    • Itching most common symptom
    • if highly inflammatory, generally acquired from animals
    • if little inflammatory, generally acquired from humans
    • Diseases:
    • - Tinea capitis: ringworm of the scalp
    • - Tinea barbae: ringworm of the beard
    • - Tinea corporis: ringworm of the glabrous skin
    • - Tinea cruris: jock itch (groin)
    • - Tinea pedis: athlete's foot
    • Diagnosis: KOH only hyphae, Microsporum also fluoresces a bright yellow green w/ wood's lamp
  3. Sporothrix schenckii
    • dimorphic fungus: on plants found as hyphae, in tissues found as Cigar-shaped yeast
    • Diseases
    • - Sporotrichosis (rose gardener disease): traumatically introduced into the skin, causes local pustule or ulcer with nodules along draining lymphatics (ascending lymphagitis). Little systemic illness
    • - Pulmonary sporotrichosis: urban alcoholics, particularly homeless (alcoholic rose garden sleeper disease) is systemic.
    • Rx: Itraconazole or potassium iodide
  4. Candida albicans
    • Forms germ tubes at 37 deg C in serum. Forms pseudo-hyphae and true hyphae when it invades tissues
    • Perleche: Crevices of mouth, malnutrition
    • Oral thrush, Esophagitis, gastritis, septicemia, endocarditis, cutaneous infections, yeast vaginitis, chronic mucocutaneous candidiasis (CMC): endocrine defects
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Derm Micro
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