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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
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