Module 2 Cutaneous Mycoses - Superficial

LESSON #2: MYCOSES TOPIC OUTLINE: I Mycoses II Superficial Mycoses III Diseases associated with superficial mycoses A Keratitis B Otomycosis C Piedras D Pityriasis versicolor E Tinea nigra LAYERS OF THE SKIN  FACTORS IN IDENTIFYING MYCOTIC DISEASE 1. In almost all cases, fungi disease...

LESSON #2: MYCOSES TOPIC OUTLINE: I Mycoses II Superficial Mycoses III Diseases associated with superficial mycoses A Keratitis B Otomycosis C Piedras D Pityriasis versicolor E Tinea nigra LAYERS OF THE SKIN  FACTORS IN IDENTIFYING MYCOTIC DISEASE 1. In almost all cases, fungi diseases are chronic. 2. History 3. Such factors as diabetes, cancer, alcoholism, AIDS, surgery, administration of immunosuppressive agents or antibiotics predispose one to systemic mycoses 4. Only one fungus disease has a very clear-cut clinical picture o Sporotrichosis: lesions lining up towards lymphatic area; caused by Sporothrix schenckii 5. The appearance of the organism in tissues CATEGORIES OF MYCOSES 1.CUTANEOUS SUPERFICIAL DERMATOPHYTOSES 2. SUBCUTANEOUS 3. SYSTEMIC 4. OPPORTUNISTIC SUPERFICIAL MYCOSES KERATITIS “MYCOTIC KERATITIS, KERATOMYCOSIS” It is a fungal infection affecting the cornea of the eyes. It is a serious mycotic disease which may lead to loss of vision. CAUSATIVE AGENTS: Fusarium, Aspergillus, Curvularia, Penicilium, Cephalosporium, Candida spp. Fusarium Aspergillus Curvalaria Penicillum Cephalosporium KERATITIS Microscopic Exam: All the etiologic agents are moulds, except Candida, and they all appear as clear, septate hyphae. Candida appears as numerous yeast cells with strands of pseudohyphae. KERATITIS Clinical Presentation: Usually a white plaque forms on the cornea. The plaque grows very slowly and eventually it may ulcerate. Characteristics of fungus involvement of the eye is the development of satellite lesions and endothelial plaques. Impairment of vision usually occur.  KERATITIS THERAPY Topical Application of: AMPHOTERICIN B but it is toxic to the retina of eye. NATAMYCIN (5-flurocytosine or 5% pimaricin) it is the drug of choice but it is very expensive and difficult to obtain. OTOMYCOSIS “FUNGUS EAR, MYCOTIC OTITIS EXTERNA” a chronic fungus infection of the outer ear and ear canal. CAUSATIVE AGENTS: most commonly reported organism that cause this disease belongs to the genera of Aspergillus, Mucor, Penicillum, Rhizopus. Aspergillus Mucor Rhizopus Clinical Presentation: Initially, the infection may be mild, resulting in only minor irritation; however, as it become more chronic, the infected area & surrounding ear tissue become inflamed. Pus may develop, and considerable amounts of debris may form inside the ear canal. OTOMYCOSIS THERAPY Clean and aerate the ear canal with a cotton swab saturated with BURROW’S SOLUTION. SUPERFICIAL MYCOSES Non-Dermatophytic Tinea 1. Tinea versicolor (Pityriasis Versicolor) Characterized by discoloration or depigmentation and scaling of skin Becomes apparent in individuals with dark complexions or in those who fail to tan normally. Caused by yeast: Malassezia furfur Common endogenous skin colonizer  Malassezia furfur Pityrosporum furfur/P. orbiculare/P. ovale Characterized by: Patchy lesions or scaling of varying pigmentation May involve chest, trunk or abdomen Identified in: KOH Preparation- Skin Scraping Yellow Fluorescence- Wood’s Lamp Microscopic Exam: fungi with budding yeast along with septate, sometimes branched hyphae Culture: Not essential for identification in routine fungal media. Hyphae is not demonstrated on routine media  Malassezia furfur 1% Selenium Sulfide: Temporary Remedy Other Associated Diseases: Folliculitis, Obstructive Dacryocystitis, Seborrheic Dermatitis in patients with AIDS, opportunistic fungemia in patients receiving total parenteral nutrition (TPN) Malassezia furfur Malassezia furfur (A) Malassezia furfur colonies (B) Growth On Culture Media (left: Sabouraud’s with oil; right without oil) SUPERFICIAL MYCOSES Non-Dermatophytic Tinea 2. Tinea nigra Characterized by brown or black macular patches, primarily on the palms. Biopsy and culture of the site are important to distinguish the infection from a much more serious nonfungal disease, melanoma Causative agent: Phaeoannellomyces werneckii Hortaea werneckii Obsolete names: Phaeoannellomyces werneckii and Exophalia werneckii Cladosporium werneckii Identified in: KOH Preparation-Skin Scraping Microscopic Exam: septate hyphae elements and budding cells, dematiaceous hyphae, some of the hyphae may contain numerous chlamydospores Younger Cultures: Budding blastoconidia in clusters Annelloconidia- seen in older hyphal colonies  Hortaea werneckii Clinical presentation is similar to other conditions that misdiagnosis could occur, resulting in unnecessary surgical procedures. Often confused with: Malignant Melanoma The lesion is flat, not scaly and does not induce erythema or inflammation. Clinicians may confuse with those features of skin cancer, syphilis or other serious disease.  Hortaea werneckii H. werneckii- shiny, moist, yeastlike colonies that start with a brownish coloration, that eventually turns olive to greenish black Microscopic Exam of Colonies: one to two celled cylindrical to spindle shaped cells with some budding (annelid formation) Colonies may occasionally be mycelial. As the culture ages, colonies become filamentous with velvety-gray aerial hyphae On SDA, fungus slowly grows usually appearing within 2-3 weeks Hortaea werneckii TINEA NIGRA THERAPY: Application of topical treatment like: Mixture of 3% sulphur and 3% salicylic acid Tincture of iodine weak Whitfield’s ointment 20-30% sodium thiosulfate SUPERFICIAL MYCOSES Non-Dermatophytic Tinea 3. Piedra Confined to hair shaft Characterized by nodules-composed of hyphae and a cement-like substance that attaches it to the hair shaft. Black Piedra: Piedraia hortae White Piedra: Trichophyton ovoides or Trichophyton beigelli and Trichophyton inkin or Trichophyton cutaneum Piedraia hortae Causative Agent of Black Piedra Infections that occur on the hairs of the scalp. Produces hard, dark brown to black gritty nodules that are firmly attached to the hair shaft. These nodules consist of asci (saclike structures) containing eight ascospores. Piedraia hortae Identified in: KOH Preparation- infected hairs are removed and placed in 10-20% KOH Microscopic Exam: Thick-walled rhomboid cells containing 8 ascospores Grows on: SDA slowly at room temperature It forms dark brown or brown, restricted colonies that remain sterile  Piedraia hortae Treatment: Removal of Infected hair shafts and application of topical fungicides Clip or shave the infected area. Treat daily with anti-fungal agents such as: 1:2000 solution of bichloride of mercury 3 % sulfur ointment benzoic and salicylic acid combinations HAIR NODULES HAIR SHAFT INFECTED BY: Piedraia hortae Piedraia hortae  “BLACK AND WHITE PIEDRAS, TINEA NODOSA, CHIGNON DISEASE, BEIGEL’S DISEASE” POINT OF BLACK PIEDRA WHITE PIEDRA DIFFERENCE Causative agent Piedraia hortae Trichosporon beigelii (Trichosporon cutaneum) Microscopic Nodules are Nodules are larger, softer and appearance dark brown, discrete, almost lighter colored than black circular. When they are piedras, septate hyphae are broken open, asci containing not dematiaceous and tend to up to 8 ascospore break into arthrospores or yeast-like cells Appearance of Dark brown with metallic Look more like yeast colonies. colonies on green tinge. They are very Smooth to slightly wrinkled culture compact, have a raised and white to tan in color. center and slightly fuzzy. Found on scalp hairs facial & genital hairs Trichosporon spp. Trichophyton ovoides Trichophyton inkin Trichophyton cutaneum Trichophyton asteroids Trichosporon asahaii causes severe and frequently fatal disease in immunocompromised host Trichosporon mucoides causes systemic diseases, recovered frequently from cerebrospinal fluid (CSF)  Trichosporon beigelii (Trichosporon cutaneum) The colony resembles young colonies of Cryptococcus neoformans but it is easily differentiated on the basis of physiologic and morphologic characteristics. WHITE PIEDRA Occurs on the hair shaft Characterized by soft mycelial mat surrounding the hair of the scalp, face and pubic region Trichosporon spp. Clinical Presentation: Rare, systemic diseases caused by these fungi are frequently fatal, commonly those who have hematologic disorders or malignancies or are undergoing chemotherapy. May cause fatal systemic infections (non-specific febrile illness or pneumonia are the most common clinical manifestation)  Trichosporon spp. Identified in: KOH Mounting- intertwined septate hyphae, hyphae breaking up into oval or rectangular arthroconidia Grows in: Primary Fungal Media (rapid growth) -produce arthroconidia, hyphae, and blastoconidia The colonies are straw to cream-colored and yeastlike. It varies and can be smooth or wrinkled, dry or moist, creamy or velvety in appearance. Trichosporon spp. Identification to the species level is confirmed by: Biochemical Reactions (-) Absence of Carbohydrate Fermentation Use of Potassium Nitrate Assimilation of Sugars (+) Urease Positivity