Superficial Mycoses PDF

Superficial Mycoses: MYCOLOGY Patrick Jumar S. Buenaflor, RMT Emilio Aguinaldo College – Cavite School of Medical Technology Superficial Mycoses Superficial mycoses are cosmetic fungal infections of the skin or shaft. No living tissue is invaded and there is no cellular respo...

Superficial Mycoses: MYCOLOGY Patrick Jumar S. Buenaflor, RMT Emilio Aguinaldo College – Cavite School of Medical Technology Superficial Mycoses Superficial mycoses are cosmetic fungal infections of the skin or shaft. No living tissue is invaded and there is no cellular response from the host. Essentially no pathological changes are elicited. These infections are often so innocuous that patients are often unaware of their condition. Superficial Mycoses Mycoses Causative Agent Tinea Versicolor (Pityriasis Malassezia furfur Versicolor) Tinea Nigra Hortaea werneckii White Piedra Trichosporon spp. Black Piedra Piedraia hortae Tinea Versicolor: clinical manifestation Caused by Malassezia furfur a disease characterized by patchy lesions or scaling of varying pigmentation more commonly known as “an-an” in local dialect Lesions occurs in smooth part of the body, most frequently on the face, chest, arms, and abdomen as discrete hyper – or hypopigmented macular lesions Tinea Versicolor: clinical manifestation They scale very easily, giving the affected area a dry, or chalky appearance Common endogenous skin colonizer Reasons for overgrowth – genetic influence, poor nourishment, and excessive sweating as Common in humid, hot and tropical places High prevalence in corticosteroid therapy patients Tinea Versicolor: lab diagnosis Microscopic examination of the direct smear in KOH preparations reveals budding yeasts, approximately 4 to 8 μm, along with septate, sometimes branched, hyphal elements “Spaghetti and Meatball” appearance Requires lipid for growth in fungal medium Yeast-like colony with cream-colored, moist and smooth colonies are observed after adding an olive oil in media. It will fluoresce a yellow color in Wood’s Lamp Examination Tinea Versicolor: Treatment General approach is removal of the organisms from the skin Topical preparations containing miconazole nitrate have been used effectively in eradicating the disease Treatment with antidandruff shampoos Tinea Nigra: Clinical Manifestation Caused by Hortaea werneckii characterized by brown to black nonscaly macules that occur most often on the palms of the hands and soles of the feet Tinea nigra is characterized a dematiaceous colonial growth of yeast and hyphae. Tinea Nigra: Lab Diagnosis Direct Examination – Skin scrapings placed in 10% to 20% KOH – Microscopic examination shows septate hyphal elements and budding cells. – Younger cultures are primarily composed of budding blastoconidia, whereas the older mycelial portion of the colony shows hyphae with blastoconidia in clusters. Culture – Produces shiny, moist, yeastlike colonies that start with a brownish coloration that eventually turns olive to greenish black (SDA) Tinea Nigra: Treatment Responds readily to keratolytic agents Daily application of Whitefield’s ointment Tincture of iodine, 2% salicylic acid or 3% sulfur White Piedra: Clinical Manifestation Caused by Trichosporon spp. – Trichosporon ovoides – T. asteroides – T. cutaneum – T. inkin – T. asahaii (most important spp.) characterized by a soft mycelial mat (cream – colored soft pasty) surrounding hair of the scalp, face, and pubic region. affects hairs of scalp, axillary, genitals and face such as mustache and beard White Piedra: Lab Diagnosis Trichosporon spp. grow rapidly on primary fungal media and produce arthroconidia, hyphae, and blastoconidia The colonies are straw to creamcolored and yeastlike. Colonies are varied and can be smooth or wrinkled, dry or moist, creamy or velvety in appearance White Piedra: Treatment May be achieved simply by shaving or cutting the infected hair Topical fungicides such as bichloride of mercury (1:200) Benzoic and salicylic acid combinations 3% sulfur ointments 2% formalin Black Piedra: Clinical Manifestation Caused by Piedraia hortae an infection that occurs on the hairs of the scalp Characterized by hard, dark brown to black gritty nodules that are firmly attached to the hair shaft. The differential diagnosis includes ruling out nits of pediculosis and abnormal hair growth. Black Piedra: Lab Diagnosis Infected hairs are removed and placed in 10% to 20% KOH, the nodules may be crushed open to reveal the asci. Thick-walled rhomboid cells containing ascospores are seen. Grows slowly on Sabouraud dextrose agar at room temperature. It forms brown, restricted colonies. Black Piedra: Treatment If therapy is desired, shaving and cutting the infected hair Use of topical fungicides, bichloride of mercury Benzoic acid/salicylic acid combinations  White Piedra V.S. Black Piedra Black Piedra White Piedra Etiology Piedraia hortae Trichosporon spp. Over and around the hair On the surface of the Nodules shaft , hard, difficult to hair shaft, softer, easy detach from the hair to separate from hair Tightly packed Arthrospores and Direct Examinations dichotomous branched blastopores can be hyphae seen Presence of asci Positive Negative