Topic 16. Fungal Diseases of the Skin and Its Appendages

7/28/2019 Topic 16. Fungal Diseases of the Skin and Its Appendages

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Efi. Gelerstein 2011

Topic 16. Fungal diseases of the skin and its appendages

Dermatophyte (Thrychophyton, Microsporum, Epidermophyton) Candida, Cryptococcus (yeast) Mucor, Aspergillus (mold)

Actinomyces, Nocardia Histoplasma, Blastomyces (dimorph)

Laboratory and special examinations

1. Collect sample with scalpel blade 5-20% KOH-heated2. Culture3. Wood (black) light (Microsporia, Corynebact. Minutissimum)4. Histology (PAS (periodic acid-Schiff), methenamine silver, Gram+)5. I.c. test id reactions6. Color, morphology of the colonies7. Sabouraud culture medium (Trychophyton 14-21, Candida 2-6 days)

Dermatophyte infections (ringworm)

More than 40 species, appr.:10 common causes of human infection

1. Antropophilic Thrychophyton rubrum Thrychophyton mentagrophytes T. schnleini T. tonsurans

T. violaceum, Microsporum audouinii, Epidermophyton floccosum2. Zoophilic

T. eguinum T. verrucosum Microsporum canis

3. Geophilic Microsporum gypseum, M. manum

Cause

Three genera of dermatophyte fungi cause tinea infections (ringworm).- Trichophyton - skin, hair and nail infections.- Microsporum - skin and hair.- Epidermophyton - skin and nails.

Dermatophytes invade keratin only, and the inflammation they cause is due to metabolic products ofthe fungus or to delayed hypersensitivity


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Tinea cruris, corporis

T. floccosum, T. rubrum, T. verrucosum, M. canis, M. gypseum Pruritic superficial infection of the groin Annular - ringworm Zoophileic infection more inflammatory, deeper, marked vesiculation,

crusting peripheral enlargement, central clearing

Tinea capitis

T. tonsurans, M. canis Endothrix Trichophyton

1. Black dot type2. Kerion type (honeycomb)

EctothrixMicrosporia1. Gray patch type2. Hyperkeratosis3. Wood light

Epidemic (schools, institutions)1. M. audouinii antropophil2. M. canis zoophil

Favus T. schoenleini, T.quinckeanum1. Scutulum, fetid odor2. Deep infection-atrophy, scarring alopecia3. Therapy

- Antimycotic plus adjunctive steroid (prednisone 1 mg/kg/day 1-2 weeks)-

Antibiotics for 2 bacterial infection (Strepto)- Surgery: drain pus from Kerion lesionsTinea barbae

Pustulosus folliculitis T. verrucosum, T. Mentagrophytes Granulomatous lesion (Majocchis granuloma)


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Antimycotic therapy:

Drug Used for Used as

Amphotericin B Systemic Candida infection Local, i.vNystatin Candida LocalNatamycin (Pimafucin) Candida,

DermatophytonLocal

Miconazole

Clotrimazole

Econazole

Tioconazol

Superficial infections Local

Ketoconazole (Nizoral) Superficial Systemic infections

Local, Oral

Itraconazole (Orungal) Superficial Systemic

Oral

Fluconazole (Diflucan,Mycosyst)

Superficial Systemic infection Oral, i.v.

Terbinafine (Lamisil, Terbisil) Dermatophyton Local, oralGriseofulvin Dermatophyton OralFlucytosin Candida

CryptococcusOral, i.v.

Amorolfin (Loceryl),

Tolnaftat (Chinofungin),

Cyclopiroxolamine (Batrafen)

Superficial infection Local

Systemic antimycotic therapy:

Cytochrome P450 metabolisation, interactions: terfenadin, astemizol, cizaprid, lovastatin,midazolam, triazolam, Syncumar, digoxin, cyclosporin, methylprednisolon, vinca-alkaloids,

tacrolimus, Ca-channel blockers, quinidin, tricyclic antidepressants, beta- blockers, SSRI, MAOi.

Rifampicin stimulates, cimetidin inhibits / decreases the cytochrom P450 system Gastric hypoacidity inhibits absorbtion

Onychomycosis - Diseases of the nail bed

Paronychia- inflammation involving the folds of tissuearound the finger nails

Acrodermatitis enteropathica (Zn replacement) Unguis incarnates

- Therapy: conservative, surgical Therapy of Onychomycosis:

1. Lamisil 250mg/day - 6 w (hand), 12 weeks (foot)2. Orungal 2x2 capsule for 7 days, 3 weeksbreak -

2 months (hand), 4 months (foot)


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Candida infections:

Part of the normal flora Predisposition: immunosuppression, diabetes, dark, humid environment, maceration Mycotic intertrigo Genital infections: balanoposthitis, balanitis, vulvitis, vulvovaginitis

Diaper dermatitis Folliculitis Paronychia

Oropharyngeal Candidiasis

Atrophic, pseudomemranous, leukoplakia, angulus infectiosus oris Deep mucosal Candidiasis: esophagus, tracheobronchial Invasive Candidiasis: neutropenia, sustained catheter (In vagina Candida without symptoms - doesnt need therapy)

Chronic mucocutaneous Candidiasis

Decreased cellular immunoreactivity against Candida antigens Often together with endocrine diseases:

1. Hypoparathyroidism, hypoadrenalism,2. Hypothyroidism, diabetes mellitus3. IPEX syndrome Foxp3 mutation (Immunodysregulation Polyendocrinopathy Enteropathy X-

linked syndrome)

Pityriasis versicolor

Pityrosporum ovale or Malassezia furfur (yeast) Foliculitis, seborrhoeic dermatitis Primarily predisposition Wood - light: green Dicarboxyl acid, inhibits the function of tyrosinase enzyme , hypomelanosis

Cryptococcosis

Cryptococcus neoformans soil, defecation of pigeon Abscess hematogenous spreading on the skin molluscum contagiosum-like papules

Lung: aspecific symptomes CNS: symptomes of meningitis, presence of fungus or fungal antigen in the liquor

Cryptococcus neoformans

Diagnosis made by staining / culture / serology Therapy:

1. Fluconazol2. Amphotericin B3. Amphotericin B + flucytosin

Or together


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Aspergillosis

Aspergillus fumigatus, Aspergillus niger infections are rare despite the high frequency of this mouldin the environment hematologic, HIV-infected and immune suppressed patients

Skin: abscess, outer ear Lung: eosinophilia

Surgical elimination of aspergilloma

Skin lesions examination:

The following tips will help improve your skills in diagnosing skin lesions:

1. Develop a logical and systemic approach to skin examination2. Try to examine the skin in a room with daylight. Examine the entire skin surface during the first

dermatologic examination. This should include:

Palms and soles, ears, submammary, interdigital, axillary, inguinal, genital, and perianal skin. Adjacent mucosa including lips, mouth, conjunctivae, nasal mucosa, and in some instances

anus.

Skin appendages (hair and nails) as well as scalp. Screening for malignant melanoma and other skin malignancies. Assessment of general skin appearance (color, texture, dryness, hydration, odor). Evidence for exposure to sunlight, nicotine, other noxious agents.

3. Match objective evidence to subjective complaints4. A total skin examination5. Look with your fingers.6. Determine the anatomic location of the lesion (epidermal, dermal or subcutaneous, skin appendages,

blood vessels, or nerves involved?

7.

Determine the primary symptom8. Become skilled in using simple diagnostic aids

History of present skin condition

Duration Site at onset, details of spread Itch / Burning / Pain Wet, dry, blisters Exacerbating factors

General health at present Ask about fever

Past history of skin disorders

Past general medical history Inquire specifically about asthma and hay fever

Family history of skin and other disorders If positive inherited vs. infection/infestation

Social and occupational history

Hobbies Travels abroad Relationship of rash to work and holidays Alcohol intake

Drugs used to treat present skin condition Topical / Systemic / Physician prescribed / Patient initiated

Topic 16. Fungal Diseases of the Skin and Its Appendages

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