Microbial Diseases Of The Skin And Eyes


Objectives: Fungal and Parasitic Diseases of the Skin


For each microbial disease listed give the following if applicable.

Name of the disease
Etiological agent
Transmission of the etiological agent
Signs and symptoms
Clinical diagnosis - How you diagnose the disease.
Laboratory diagnosis - Special laboratory tests used if any.
Pathology - How the organism causes the disease.


Vaginitis (candidiasis)

Fungal Diseases of the Skin and Nails


Cutaneous Mycoses


Fungi that colonize the outer layer of the epidermis cause dermatomycoses.


Microsporum, Trychophyton, and Epidermophyton cause dermatomycoses called ringworm, or tinea.


These fungi grow on keratin-containing epidermis, such as hair, skin, and nails.


Ringworm and athlete's foot are usually treated with topical antifungal chemicals.


Diagnosis is based on the microscopic examination of skin scrapings or fungal culture.



Subcutaneous Mycoses


Sporotrichosis results from a soil fungus that penetrates the skin through a wound.


The fungi grow and produce subcutaneous nodules along the lymphatic vessels.




Candida albicans causes infections of mucous membranes and is a common cause of thrush (in oral mucosa) and vaginitis.


C. albicans is an opportunistic pathogen that may proliferate when the normal bacterial microbiota are suppressed.


Topical antifungal chemicals (miconazole, clotrimazole, and nystatin) may be used to treat candidiasis.


Ketoconazole (oral) or Fluconazole (Diflucan) may be used for systemic candidiasis and Diflucan has been shown to be a better choice in most cases than topical antifungals.



Parasitic Infestation of the Skin




Scabies is caused by the mite Sarcoptes scabiei burrowing and laying eggs in the skin.


Transmission is by intimate contact, including sexual.


Treatment is with solutions of Permethrin (insecticide), Gamma benzene hexachloride (Kwell), or Ivermectin (oral).


Scabies Mites in Skin



Pediculosis is an infestation by the human louse, Pediculus humanus.


P. humanus capitus is the head louse and P. humanus corporis is the body louse.


Only the body louse spreads diseases.


Speaking of lice, there is also Pthirus pubis, pubic lice, or more commonly, crabs. Treat 'em all with Permethrin or Malathion.


P. humanus capitus Adult and Nit (egg)