Download MBBS (Bachelor of Medicine, Bachelor of Surgery) Dermatology PPT 8 Fungal Infections Lecture Notes
Fungal infections
Natural defence against fungi
? Fatty acid content of the skin
? pH of the skin, mucosal surfaces and body fluids
? Epidermal turnover
? Normal flora (bacterial; fungal)
Predisposing factors
? Climate: Tropical, profuse sweating
? Manual labor population
? Lower socioeconomic status
? Friction with clothes, synthetic innerwear
? Malnourishment
? Immunosuppressed patients: HIV infection/AIDS,
congenital immunodeficiencies, patients on
corticosteroids, immunosuppressive drugs
(posttransplant), diabetes mel itus
Fungal infections: Classification
v Superficial cutaneous:
Surface infections e.g., Pityriasis versicolor,
Dermatophytosis, Candidiasis, Tinea nigra, Piedra
v Subcutaneous:
Mycetoma, Chromoblastomycosis, Sporotrichosis,
Phaeohyphomycosis
v Systemic: (opportunistic infection)
Histoplasmosis, Candidiasis, Zygomycosis
Pityriasis versicolor
Etiologic agent: Malassezia furfur (formerly:
Pityrosporum)
Clinical features:
? Common among youth
? Genetic predisposition, familial occurrence
? Multiple, discrete, discoloured, macules, may be
fawn, brown, grey colored or hypopigmented
? Pinhead sized to large sheets of discolouration
?Seborrheic areas, upper half of body: trunk, arms,
neck, abdomen
P.versicolor : Investigations
? Wood's Lamp (365 nm) examination: Yel ow
fluorescence
? KOH preparation:
"Spaghetti and meatbal " appearance
Coarse mycelium, fragmented to short filaments 2-5
micron wide, together with spherical, thick-wal ed
yeasts 2-8 micron in diameter, arranged in grape like
fashion.
Treatment P. versicolor
Topical:
? Ketoconazole, Clotrimazole, Miconazole,
Terbinafine, Selenium sulfide
Oral:
? Fluconazole 400 mg single dose
? Ketoconazole 200mg OD x 14days
? Oral griseofulvin & oral terbinafine: NOT effective.
? Hypopigmentation wil take weeks to fade
? Scaling wil disappear soon
Treatment P. versicolor
?P. versicolor recurs if predisposing factors not taken
care of
?Minimizing sweat, frequent washes and control of
immunosuppression causes long remission
? Treatment: Oral Itraconazole, Ketaconazole,
Fluconazole or topical Ketoconazole shampoo.
Tinea nigra palmaris
Etiology: Hortaea werneckii (formerly: Exophiala
wernecki )
Clinical features: Asymptomatic superficial infection
of palms; deeply pigmented, brown or black macular,
non-scaly patches, resembling a silver nitrate stain.
? Treatment: Topical antifungals (e.g.,
ketoconazole)
Black piedra
?Etiology: Piedraia hortae
?Distribution: South America and in South-East Asia
?Clinical features: Hard, dark, multiple superficial
nodules; firmly adherent black, gritty, hard nodules
on hairs of scalp, beard, moustache or pubic area,
hair may fracture easily.
?Treatment:
Shaving or cutting the hair.
Terbinafine
White piedra
Etiology: Trichosporon beigeli
Clinical features:
Soft, white, grey or brown superficial nodules on
hairs of the beard, moustache , pubic areas.
Hair shaft weakened and breaks.
Treatment: Shaving or cutting the hair. Responses to
topical antifungals, azoles and al yamines have been
reported but are unpredictable.
Dermatophytosis
Mycology:
?Three genera:
Microsporum, Trichophyton, Epidermophyton
?They can be zoophilic, anthropophilic or geophilic.
?Thrive on dead, keratinized tissue - within the stratum
corneum of the epidermis, within and around the fully
keratinized hair shaft, and in the nail plate and
keratinized nail bed.
Dermatophytes are keratinophillic
?The topmost layer (stratum corneum) is a sheet of non
-nucleated cel s (corneocytes) containing protein ?
keratin ? stuck together forming a tough barrier
? This barrier, when dry al ows fungi to stay on the
surface but stops them from piercing it
? However, when moist, it becomes porous and sucks in
the fungi like a sponge.
Dermatophytosis (Ringworm)
vTerminology:
?Head: Tinea capitis
?Face: Tinea faciei
?Beard: Tinea barbae
?Trunk/body: Tinea corporis
?Groin/gluteal folds: Tinea cruris
?Palms: Tinea manuum
?Soles: Tinea pedis
?Nail: Tinea unguium
Tinea capitis
Invasion of hair shaft by a dermatophyte fungus.
Clinical features:
?Common in children with poor nutrition and hygiene.
Rare after puberty because sebum is fungistatic.
?Wide spectrum of lesions - a few dull-grey, broken-off
hairs, a little scaling to a severe, painful, inflammatory
mass covering the scalp.
?Partial hair loss is common in al types; cicatricial
(scarring ) alopecia can occur
Tinea capitis
Endothrix and Ectothrix
Term used to indicate infection of hair shaft, spores
lying inside or outside hair shaft.
4 varieties:
?Gray patch
?Black dot
?Favus
?Kerion (similar to a `boil')
Non inflammatory Tinea capitis:
Black dot/ Grey patch
? Breakage of hair gives rise to `black dots'
?Patchy alopecia, often circular, numerous broken-off
hairs, dull grey
? Inflammation is minimal
?Wood's lamp examination: green fluorescence
(occasional non-fluorescent cases)
Tinea capitis: Kerion
Inflammatory variety
Painful, inflammatory boggy swel ing with purulent
discharge.
Hairs may be matted, easily pluckable
Lymphadenopathy
Co-infection with bacteria is common
May heal with scarring alopecia
Tinea capitis: Favus
Inflammatory variety
Yel owish, cup-shaped crusts (scutula) develop around
a hair with the hair projecting central y. Adjacent
crusts enlarge to become confluent mass of yel ow
crusting.
Hair may be matted
Extensive patchy hair loss with cicatricial alopecia
Tinea faciei
Erythematous scaly patches on the face
Annular or circinate lesions and induration
Itching, burning and exacerbation after sun exposure
Seen often in immunocompromised adults
Tinea barbae
Ringworm of the beard and moustache areas
Invasion of coarse hairs
Disease of the adult male
Highly inflammatory, pustular fol iculitis
Hairs of the beard or moustache are surrounded by
inflammatory papulopustules, usual y with oozing or
crusting, easily pluckable
Persist several months
Tinea corporis
Lesions of the trunk and limbs, excluding ringworm of
the specialized sites such as the scalp, feet and groins
etc.
The fungus enters the stratum corneum and spreads
centrifugal y. Central clearing results once the fungi
are eliminated.
A second wave of centrifugal spread from the original
site may occur with the formation of concentric
erythematous inflammatory rings.
Tinea corporis
Classical lesion:
Annular patch or plaque with erythematous
papulovesicles and scaling at the periphery with
central clearing resembling the effects of ring worm.
Polycyclic appearance in advanced infection due to
incomplete fusion of multiple lesions
Sites: waist, under breasts, abdomen, thighs etc.
Tinea cruris
Itching
Erythematous plaques, curved with wel demarcated
margins extending from the groin down the thighs.
Scaling is variable, and occasional y may mask the
inflammatory changes.
Vesiculation is rare
Tinea mannum
Two varieties:
Non inflammatory: Dry, scaly, mildly itchy
Inflammatory: Vesicular, itchy
Tinea pedis
Wearing of shoes and the resultant maceration
Adult males commonest, children rarely
Peeling, maceration and fissuring affecting the lateral
toe clefts, and sometimes spreading to involve the
undersurface of the toes.
Two varieties:
Dry, scaly, mildly itchy, extensively involved ('moccasin foot
`)
Vesicular, itchy, with inflammatory reactions affecting
al parts of the feet
Tinea pedis : Prevention
Keeping toes dry
Not walking barefoot on the floors of communal
changing rooms
Avoiding swimming baths.
Avoid closed shoes
Avoid nylon socks
Use of antifungal powders
Tinea Unguium
Dirty, dull, dry, pitted, ridged, split, discoloured,
thick, uneven, nails with subungual hyperkeratosis
Different types described depending on the site of nail
involvement and its depth.
Distal and lateral onychomycoses
Proximal subungual onychomycoses
White superficial onychomycoses
Total dystrophic onychomycoses
Treatment: Ringworm
Topical: Ketoconazole, Clotrimazole, Miconazole,
Butenafine, Terbinafine.
Vehicle: Lotions, creams, powders, gels are available.
Treatment: Tinea
Oral: Griseofulvin 250 mg BD
Fluconazole 150 mg weekly
Ketoconazole 200 mg OD
Terbinafine 250 mg OD
Itraconazole 200 mg OD
Duration: T. capitis - 6 weeks
T. faciei - 4 weeks
T. cruris - 4 weeks
T. corporis - 4-6 weeks
T. manuum/pedis - 6-8 weeks
Shorter duration required for terbinafine & itraconazole
Treatment: Tinea unguium
The same line of Treatment for 3 months (fingernail)
to 6 months (toenails)
8% Ciclopirox olamine lotions for local application
Amorolfine nail lacquer painted weekly
Pulse Therapy
Terbinafine: 250mg given 1BD x 1week / per month
Itraconazole: 200mg given 1BD x 1week/month
3 pulses for fingernails, 4 pulses for toenails.
Treatment Principles
Patient should be explained clearly about the
predisposing factors
Need for personal hygiene, proper clothing should be
emphasized
Selection of topical medication:
Do not use ointments on areas of friction or on greasy
areas
Do not rub creams/ointments in groin folds
Choose steroid combinations only if itch is a major
complaint. Do not use antifungal creams in
combination with potent steroids
Treatment Principles
Dermatophytosis wil take 3-4 weeks to resolve and
patient should be told about the need for complete
treatment. Treat 1 week beyond apparent cure.
Need for hygiene, proper clothing.
Onychomycosis requires 3-6 months of treatment.
Treat 4 weeks beyond apparent cure.
Temporary relief should not be mistaken for cure
Candidiasis
Causative organism:
Candida albicans, Candida tropicalis, Candida
pseudotropicalis
Sites of affection:
Mucous membrane
Skin
Nails
Candidiasis : Mucosal
Oral thrush:
Creamy, curd-like, white pseudomembrane, on
erythematous base
Sites:
Immunocompetent patient: cheeks, gums or the
palate.
Immunocompromised patients: affection of tongue
with extension to pharynx or oesophagus; ulcerative
lesions may occur.
Angular cheilitis (angular stomatitis / perleche):
Soreness at the angles of the mouth
Candidiasis : Mucosal
Vulvovaginitis (vulvovaginal thrush): Itching and
soreness with a thick, creamy white discharge
Balanoposthitis:
Tiny papules on the glans penis after intercourse,
evolve as white pustules or vesicles and rupture.
Radial fissures on glans penis in diabetics.
Vulvovaginitis in conjugal partner
Candidiasis - Flexural
Intertrigo: (Flexural candidiasis):
Erythema and maceration in the folds; axil a, groins and
webspaces.
Napkin rash:
Pustules, with an irregular border and satel ite lesions
Candidiasis: Nail
Chronic Paronychia:
Swel ing of the nail fold with pain and discharge of
pus.
Chronic, recurrent.
Superadded bacterial infection
Onychomycosis:
Destruction of nail plate.
Treatment of candidiasis
Treat predisposing factors like poor hygiene,
diabetes, AIDS, conjugal infection
Topical:
Clotrimazole, Miconazole, Ketoconazole, Ciclopirox
olamine
Oral:
Ketoconazole 200mg, Itraconazole 100-200mg and
Fluconazole 150mg
This post was last modified on 07 April 2022