1. Superficial Mycoses
Dr. Pendru Raghunath Reddy

2. SUPERFICIAL MYCOSES
The superficial mycoses are usually confined to the
outermost layer of skin, hair, mucosa and do not invade
living tissues

3. Superficial mycoses
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Do not elicit immune response
No discomfort
Cosmetic problems
Limited to stratum corneum

4. Superficial Mycoses
1. Pityriasis versicolor
2. Tinea nigra
3. Black piedra
4. White piedra

5. Pityriasis Versicolor
 Caused by Malassezia furfur (Pityrosporum orbiculare)
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lipophilic yeast
Found as a normal flora on the skin
Rich in sebaceous glands
Grows on media supplemented with fatty acids
Exist in budding yeast,occasionally hyphal
Diseases :
 Pityriasis versicolor
 Pityriasis folliculitis
 Seborrhoeic dermatitis; Dandruff
 Systemic infection

6. Major clinical manifestations:
– Hyper- or hypopigmented of the skin
– Lesions are well-demarcated (white, pink or
brownish)
– Fawn-colored macules are the most common
presentation
 Trunk and upper arms
 Rarely on neck and face

10. Pityriasis folliculitis
 follicular papules and pustules
 back, chest and upper arms
 sometimes the neck, seldom the face
 Itchy and often appear after sun exposure

11. Pityriasis folliculitis

12. Seborrhoeic dermatitis
 Changes in quantity and composition of sebum
 increase in wax esters
 shift from triglycerides to shorter fatty acid chains
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Increase in alkalinity of skin
 External local factors such as occlusion

13. Clinical manifestations:

Erythema and scaling in areas with a rich supply of
sebaceous glands
 scalp, face, eyebrows, ears and upper trunk
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Lesions are covered with greasy scales
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Itching is common in the scalp

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15. Laboratory diagnosis
Specimen: Skin scrapings
Methods:
1. KOH preparation
2. Culture
KOH preparation
Both budding yeast cells and hyphae can be demonstrated
Shows characteristic ‘spaghetti and meatballs’ appearance

16. •Short fragments
of hyphae
•clusters of yeast
• Spaghetti and meatballs
appearance

17. Culture
M. furfur requires fatty acids for growth, hence is cultured on SDA
with a layer of olive oil
Colonies of M. furfur on Dixon's agar. A specialized isolation
medium containing glycerol-mono-oleate

18. Management and Treatment:
1. Topical agent: imidazole (Ketoconazole shampoo)
2. Oral treatment : ketoconazole, itraconazole
3. Alternative: zinc pyrithione shampoo
•
selenium sulfide lotion
•
propylene glycol 50% in water twice daily

19. TINEA NIGRA
• Tinea nigra is an infection of keratinised layer of skin
caused by Exophiala werneckii or Cladosporium
werneckii
• C. werneckii is a dimorphic fungus that produces
melanin

20.  A well-demarcated brown-black macular lesions which usually
occur on the palmar aspects of hands and occasionally the
plantar and other surfaces of the skin
 Lesions are non-inflammatory and non-scaling
•palmar
•brown
•no scaling
•no inflammation

21. Laboratory diagnosis
KOH preparation
Microscopy of the KOH preparation of skin scrapings collected
from the affected part
Typical darkly pigmented yeast-like cells and hyperfragmented
hyphae are demonstrated

22. Culture
 Initially colonies are mucoid, yeast-like and shiny black
(young yeast)
 Abundant aerial mycelia and become velvety, dark olivaceous
in colour. (mature mould)

23. Management & Treatment
 Sulfur soap, SSA, azoles
 Topical treatment
 Whitfield's ointment (benzoic acid compound)
 Imidazole agent twice a day for 3-4 weeks
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24. Black Piedra
• Black piedra is a superficial infection of the hair caused by
Piedraia hortae, a dematiaceous fungus
Clinical Manifestations
 Does not penetrate the hair follicle
 presence of hard nodules found along the infected hair
shaft
 Nodules: hard, fusiform, firmly attached to hair shaft

25. Laboratory diagnosis
Demonstration of nodules containing asci with spindle shaped
ascospores in 10% KOH mount of the hair

27. Culture

28. Management and Treament
 Shave or cut the hairs short
 Terbinafine
 Dose: 250 mg a day for 6 weeks

29. White Piedra
• Infection of the hair caused by yeast-like organism
Trichosporon beigelli
• Commonly found in South America, Central and Eastern
Europe and Japan
• The hair of scalp, moustache, and beard are commonly
affected
• The development of a soft, pasty, cream-colored growth
along infected hair shaft characterizes the condition
• The initial growth occurs beneath the epidermis of hair
• The infected hair shaft consists of mycelium that rapidly
fragments to arthroconidia

30. In this picture we see hair with white piedra (Trichosporon beigelii).
Note that, when this module is compared with that seen in black
piedra, it is not as discrete and lacks the dark coloration. Additionally,
this fungus does not produce ascospores. When cultured on
Sabouraud’s agar and incubated for 2-4 weeks at room temperature,
this fungus produces a rough, membranous, white to light tan colony.
Microscopically, the organism produces no characteristic spores.

31. Laboratory diagnosis
1. Direct Microscopy
Fragmented hyphae that develop into arthroconidia or produce
blastoconidia in 10% KOH mount of hair

32. 2. Culture
Grown on SDA with cycloheximide
White or yellowish to deep cream colored
Smooth, wrinkled, velvety, dull colonies with a mycelial fringe
This is a 4-5 weeks old culture of Trichosporon beigelii
grown on SDA agar at room temperature

33. Management and Treatment
 Shave the hairs
 Topical: imidazole agent