it is based on Harrisons and Davidson text book of internal medicine and Anathanarayanan textbook of microbiology. many clinical pictures have been embeded for better understanding. most common conditions seen in dermatology wards.
2. Types of superficial mycoses
• Two types:
• Surface infections
• Cutaneous infections
3. Surface infections
• fungi live exclusively on dead layers of skin
and its appendages.
• No contact with living tissue, so no
inflammatory response.
• only cosmetic effects.
• Eg. Tinea (Pityriasis) versicolor, Tinea nigra,
Piedra
4. Cutaneous infections
• Infection is confined to cornified layer of skin
and its appendages.
• So various inflammatory & allergic responses
are produced by fungal metabolic products.
• Most common dermatophytoses caused by
dermatophytes.
5. Candida sp. (albicans)
• Cause infection of skin and mucosa as well as
systemic infections.
• Clinical features:
• Oropharyngeal & vaginal candidiasis,
intertrigo and chronic paronychia.
• Often follows antibiotic therapy.
• Common in diabetes mellitus & HIV infection
• Treatment: topical azoles
• Oral azoles for refractory & recurrent disease
7. Pityriasis versicolor
• Localised infection of stratum corneum.
• Cause – Malassezia furfur, lipophilic fungi
• Clinical features: discrete or confluent macular
areas of hypo or hyperpigmented scaly
patches on chest, abdomen, upper limbs and
back.
• Usually asymptomatic but can be pruritic
• Also cause folliculitis, seborrheic deramatitis.
8. Seborrheic dermatitis
• Erythematous pruritic scaly lesion in
eyebrows, moustache, nasolabial folds, scalp.
• Cradle cap – scalp lesions in babies.
• Dandruff – scalp lesions in adults.
• Severe in patients with HIV.
9. Diagnosis:
• clinical
• skin scrapings in KOH mount shows
abundance of yeast-like cells & short,
branched septate hyphae.
• Fungal growth in Sabouraud agar with olive oil
for disseminated infection
10. Treatment:
• Topical creams and lotions
• Selenium sulphide shampoo or cream
terbinafine, ciclopirox cream for 2 weeks.
• For extensive disease, itraconazole or
fluconazole – 5-7 days.
• these are benign, self limited but recurrences
are the rule.
11. Tinea nigra
• Localised infection of stratum corneum.
• Cause – Expophiala werneckii & castellani
• Diagnosis: skin scrapings show brownish,
branched, septate hyphae and budding cells.
• Grey or black colonies in Sabouraud agar.
• Treatment: topical antifungals
12. Piedra
• Cause:
Black piedra – Piedraia hortae
White piedra – Trichosporon beigelii
• Clinical features:
• Fungal elements as firm, irregular nodules
cemented along the hair shaft.
• Treatment: topical antifungals
13. Cutaneous mycoses- Deramtophytoses
• Commonly called Tinea or ring worm.
• Cause: dermatophytes, kertinophilic fungi.
• Affect skin, hari & nails.
• Enzymatically digest keratin but doesnot affect
living tissues.
• Resistant to chlorheximide.
14. Pathogenesis
• occur Worldwide
• Transmitted by person-to-person contact &
fomites.
• Infection from cats, dogs & soil.
• More common in male – progesterone have
been shown to inhibit growth.
• Ring lesions grow outward in centrifugal
pattern.
15. Id reaction
• Hypersensitivity fungal antigens elicit
inflammatory response.
• The reaction may follow oral antifungal
therapy and can be confused with an allergic
drug reaction.
• These sterile vesicular lesions are called
deramatophytids (id reaction)
• Hypersensitivity demonstrated by skin testing
with fungus antigen trichophytin.
16. Cinical features
• Tinea capitis – head
• Tinea pedis – feet
• Tinea corporis – body
• Tinea cruris – crotch
• Tinea unguium –nails
• (onychomycosis)
17. Tinea capitis
• Two types
• Favus- dense crusts in hair
follicles, cause scarring &
aloepicia
• Kerion – severe boggy lesions with marked
inflammatory reaction.
• Commonly in 3-7 years
18. Tinea corporis
• Well demarcated, annular, pruritic, scaly
lesions that undergo central clearing.
• One or several lesions is present.
• Involve trunk with folliculitis and pustule
formation.
• Should be differentiated from contact
dermatitis, eczema and psoriasis.
19.
20. Tinea pedis
• Starts in web spaces of toes
• Peeling, maceration and scaly pruritic rash
along lateral and plantar aspects.
• Hyperkeratosis often ensues
• Implicated in lower extremity cellulitis
21. onychomycosis
• Common in older adults, patients with vascular
disease, diabetes mellitus & trauma.
• Treating for cosmetic reasons alone is discouraged.
22. Tinea cruris
• Almost exclusively in men
• Perianal rash is erythematous, pustular, with
discrete scaly border.
• Affected area should be kept as dry as possible
23. Diagnosis
• Mainly clinical
• scrapings of skin, hair, nail in KOH mount shows
non-pigmented branching hyaline septate.
• Plucked hair in woods lamp shows 2 types.
Ectothrix – spores
surrounding hair shaft
Endothrix – spores inside hair shaft
24. Culture
• Indicated if an outbreak is suspected or
doesnot respond to therapy.
• Helps in identification of causal fungus and
treatement.
25. Treatment
• Topical creams are effective.
• Lotions, sprays for hairy areas
• Oral therapy for Extensive skin lesions (1-2
weeks) and onychomycosis (3 months) –
• oral itraconazole – 200mg/day
• Oral terbinafine – 250 mg/day
• Relapses are coomon & should be treated
early with topical therapy.