Medical Mycology: Superficial, Cutaneous and Subcutaneous Mycoses Hugh B. Fackrell

Mycoses & Mytoxicosis Mycoses: fungal infections Mytoxicosis: intoxicaton

Fungal Disease Mycoses Colonization of the host Mycotoxicosis: Intoxication Hypersensitivity

Fungal Entry Rarely cause disease in healthy person Commensal Candida albicans Malasseza fufur Underlying disorder trauma immunological deficiency debilitating conditions

Disease Mechanisms of Fungi Exogenous Opportunistic inhalation Superficial Trauma hygiene Cutaneous trauma Subcutaneous Systemic Endogenous Opportunistic Iatrogenic (physician induced) e.g. indwelling lines catheters

Fungal Dissemination Breach in host defenses Must repair defect endocrinopathies immune disorders iatrogenic Must repair defect

Host Defense Factors Intact skin long chain fatty acids pH Bacterial antagonism corneum stratum desiccated epithelial cell turnover rate (0.5 kg/yr.) Mucous membranes ciliated antimicrobials Immunological competence

Fungal Infections Superficial fungal infections Cutaneous Mycoses Opportunistic Infections Superficial fungal infections Cutaneous Mycoses Subcutaneous Mycoses Systemic Mycoses

Structure of Skin

Superficial Fungal Infections Skin Infections limited to Stratum corneum do not penetrate deeper tissues No inflammation

Superficial mycoses Pityriasis versicolor Black piedra White piedra tinea nigra http://fungusweb.utmb.edu/mycology/piedraia.html

Black Piedra Superficial mycosis Piedraia hortai small firm black nodule Surrounds hair shaft

White Piedra Superficial mycosis Trichasporon beigelii soft friable beige nodule distal ends of hair shaft

Pityriasis Versicolor Common superficial mycosis Superficial keratin layer hypo or hyper pigmentation on skin of neck shoulders chest and back Malassezia furfur

Malassezia furfur http://fungusweb.utmb.edu/mycology/hairskinnail-infections.html

Tinea Nigra Superficial mycosis Phaeoannellomyces werneckii silver nitrate type of stain palm of hand http://fungusweb.utmb.edu/mycology/hairskinnail-infections.html

Cutaneous Mycoses Dermatophytoses Dermatomycoses

Dermatophytoses Cutaneous Mycoses Secrete keratinolytic enzymes which dissolve the skin protein KERATIN Three genera Epidermophyton. Microsporum, Trichophyton Anatomic specificity correlates with genus -skin,hair,nails.

Epidermophyton

Microsporum

Spores on outside of hair follicle Microsporum Ectothrix Spores on outside of hair follicle

Microsporum

Microsporum

Microsporum Spores of Microsporum lie outside the hair shaft. This is known as ECTOTHRIX Can be seen with an ultra violet lamp called a “Woods” light. Bright fluorescence. Children are more susceptible than adults, because post pubertal sebum has fungistatic fatty acids especially M.audouinii

Microsporum audouinii,canis M.audouinii -Predominant species in temperate climates. Very contagious can cause epidemics Spread by barbers tools, seat head rests M.canis- Second most common- spread by kittens, pups - young animals

Trichophyton

Trichophyton

Trichophyton

Trichophyton

Dermtaophytes: Tinea Infections Tinea capitis - Head, scalp, neck Tinea barba - Face Tinea corporis - Body Tinea.cruri - Groin, perineum Tinea pedis - Feet Tinea unguium -Nails TINEA means RINGWORM

Tinea capitis Ringworm of the scalp-very contagious- especially pre-pubertal children. Begins with small, itchy, scaling papule spreads peripherally makes a roundish lesion, Hair breaks off at scalp level, leaving a patch.

Tinea Capitis

Tinea corporis Ringworm of the body,with annular lesions the centre is scaly and the periphery advancing circle of vesicles and papules. Prefers areas that are hairy soon to become bare due to the fungus. Associated with poor nutrition and hygiene but is also common in persons who frequent gymnasiums and pools.

Tinea pedis Tinea pedis - “Athletes foot”skin cracks between toes, maceration of tissue,desquamation, ulcerations, can spread whole bottom foot. Epidermophyton and Trychophyton. ~ 2% carry fungus no symptoms.men susceptible

Tinea Pedis

Tinea cruris T.cruris- Groin, perineum,perianal region Epidermophyton floccosum or inguinale. Tight pants,perspiration,pubic contact. Epidermophyton and Trychophyton. ~ 2% carry fungus no symptoms.men susceptible

Tinea Cruris Epidermophyton

Tinea unguium Nails brittle thick,discoloured, grooved. Trichophyton rubrum most common in women aged 40-50 Persistent very difficult to treat. Antibiotics cannot be effective.

Dermatomycoses Cutaneous fungal infections inflammation caused by opportunistic fungi Candida spp

Cutaneous Mycoses: Treatment Mild cases topical treatment 3% sulfur+3% salicylic acid ointment 1% crystal violet 1% iodine 1% tolnaftate 10% undecylenic acid miconazole haloprogin

Cutaneous Mycoses Treatment Serious or stubborn cases Griseofulvin - 1gram /day for 1-3 months This antimicrobial extracted from cultures of Penicillium griseofulvum in 1939 not used as a drug until 1959

Subcutaneous Mycoses Caused by trauma [puncture]and introduction of the fungus and bacteria. Chromoblasomycosis Phaeohypomycosis Mycetoma Sporotrichosis

Chromoblastomycosis Subcutaneous mycosis verrucoid skin lesions lower extremities Histology muriform cells- cross walls in two directions no involement of bone tendon or muscle

Phaeohypomycosis Infections caused by dermatiaceous fungi hyphal to yeast forms in tissue Dermatiaecous Fungi melanin black fungi

Mycetoma Granulomatous local lesions Suppuration usually of the legs and feet infect humans who have extensive contact with soil and foliage due to bare feet and legs. Suppuration small visible pigmented grains or granules microcolonies Destroys bone tendon and muscle

Mycetoma Madura foot caused by many organisms Eumycotic mycetoma fungal USA Pseudallescheria boydii Actinomycotic mycetoma bacterial USA Nocardia brailiensis Madura foot

Sporotrichosis world wide-Sporothrix schenkii ulcerative lesions at site on injured skin usually arm, spread to the regional lymph nodes. The high risk group, gardeners, farmers who work with wood/ soil. Highly infectious on contaminated dressings to patients with wounds.

Sporotrichosis

Sporotrichosis

Sporotrichosis

Treatment of sporotrichosis topical potassium iodide amphotericin B systemically.