Black fungi, also known as dematiaceous fungi, are a diverse group of slow-growing fungi found in soil worldwide. They can cause two types of infections in humans: chromoblastomycosis and phaeohyphomycosis. Chromoblastomycosis is a localized fungal infection of the skin caused by fungi such as Fonsecaea pedrosoi. It presents as verrucous lesions on exposed areas like the feet and legs. Phaeohyphomycosis is a subcutaneous or systemic infection caused by various dematiaceous fungi presenting as abscesses or lesions. Both infections are diagnosed by microscopic examination of skin or tissue samples and treated with antifungal

1. BLACK FUNGI
(DEMATIACEOUS FUNGI)
BY SWETA CHAUDHARY
4th semester

2. INTRODUCTION
• “ Black fungi” sometime also called “black yeast”
or dematiaceous Fungi, micro colonial Fungi or
meristematic Fungi.
• It is diverse group of slow growing micro fungi
which reproduce most asexually .
• Only few genera reproduce by budding cell, while
in other hyphal or meristematic reproduction is
preponderant.
• They are found in soil and generally distributed
worldwide.

3. INFECTION CAUSED BY BLACK FUNGI
• Chromoblastomycosis
• Phaeophyphomycosis

4. CHROMOBLASTOMYCOSIS
• Chromoblastomycosis is slowly progressing
localized fungal infection of skin and
subcutaneous tissue mostly involving exposed
part of body without tendency to disseminate.
• This is caused by dematiaceous fungi and is
characterized by polymorphic , verrucoid ,
crusted or ulcerated lesions.
• Usually it infect feet and legs.

6. MYCOLOGY
• Causative fungus -dark brown, olivaceous or
black fungi.
• Family- Herpotrichi Ellaceae
• Order- Dothideales
• Class- Biotonicate Pyronomycetes
• Phylum- Deuteromycetes

7. EPIDEMOLOGY
• Chromoblastomycosis is common diseases among rullar
worker in tropical and subtropical countries of central and
south America as well as Africa.
• This is found prevalent in Maxico, cuba and other part of
latin America , Africa and madagascar.
• This may ocassionally be seen in temperature zone but it is
most frequently encountered in warmer climate where
people go barefoot and wear minimal clothing.
• This fungi are widely distributed as saprotrophic organism
in soil and decaying vegetation in all type of climate.
• It is also mostly seen in males residing in rular area .
• In Japan however , incidence is found to be equal in both
sexes.

8. • This infection has also been reported in
domestic animal like dogs and horses .
• The infection is non-contagious as it is not
transmitted from animal to human or mam to
man and infective from of causative fungi in
mycelial from whereas in man it is found as
sclerotic cells .

9. PATHOGENESIS
• Chromoblastomycosis is believed to originate in
minor trauma to the skin , usually from the
vegetative material such as throns or splinters.
This trauma implants fungi in the subcutaneous
tissue.
• In many cases , the patients will not notice or
remember the initial trauma , as symptoms often
do not appear for years.
• The fungi most commonly observed to cause
chromoblastomycosis are:

10.  Fonsecaea pedrosoi
 Phialophora verrocosa
 Cladophialophora carrionii
 Fonsecaea compacta
• Over months to years an Erythematous papule appears
at the site of innoculation.
• Although the mycosis slowly spreads ,it usually remains
localized to the skin and subcutaneous tissue.
• Hematogenous or lymphatic spread may occur.
• Multiple nodules may appears on the same limb,
sometimes coalesling into a large plaque.
• Secondary bacterial infection may occur ,sometimes
inducing lymphatic obstruction
• The central portion of the lesion may heal ,producing
lscar or it may ulcerate.

11. A.Cladosporium type B.Rhinocladiella type C.phialophora type
fig: types of sporulation in dematiaceous fungi causing chromoblastomycosis

12. CLINICAL FEATURES
• Warty papule enlarges to expanding varrucous plaque
,commonly on feet ,legs , neck and face.
• The verrucose lesions are frequently ulcerated and may
be raised about 1- 3 cm above the skin level with rough
irregular surfaces giving cauliflower like apperance and
hence it is called verrucose dermatitis.
• The infection is confined to skin and subcutaneous
tissue and not disseminated to deeper organs of the
body.
• Satellite lesions may also develop by auto inoculations.

13. • The lower legs are frequently affected part of the
body and rarely shoulders , arms ,hands buttocks ,
ears , chest ,face and abdomen may be involved.
• The hematogenous and lymphatic dissemination
is seen in sporotrichosisi srearly observed .
• Sometimes secondary bacterial infection may
result in lymphatic obstruction and consequently
result in elephantiasis of legs .
• The lesions may parsist for decades if neglected or
unsuccessfully treated.

14. Fig: Elephantiasis of leg

15. LABORATORY DIAGNOSIS
1.Clinical material: skin scrapings and /or biopsy.
2.Direct microscopy:
a) Skin scrapings should be examined using
10%KOH and parker ink and calcofluor white
mounts.
b) Tissue section should be stained using H&E,
PAS digest and Grocitt‘s Methanamine silver
(GMS).

16. Fig 1:sclerotic bodies seen in wet mount Fig 2:sclerotic bodies seen in H &E

17. TREATMENT
• Chromoblastomycosis responds very poorly the
available therapies.
• The therapeutic modalities may be cryotharpy
,thermotherapy, laser therapy , chemotherapy
and surgery.
• The most commonly used is flucytosine which act
by inhibatating nuclic acid synthesis and is given
orally as 50-150 mg/kg per day in far divided
dose.
• Newerazoles like itraconuzole and fluconazole
have been used efficitively.

18. PHAEOHYPHYOMYCOSIS
• Phaeohyphyomycosis is subcutaneous and systemic
infection , caused by various heterogenous group of
dematiaceous fungi .
• These fungi are found in hyphal form in tissue and not thick
walled muriform cell and seen in chromoblast mycosis.
• The term phaeohyphomycosis is derived from Greek word
‘Phaios’ means dark and refer to brownish black colour and
fungi in vivo and cell in in vitro .
• It compare group of infection ranging from superficial ,
cutaneous or subcutaneous infection to disseminated invas
have diseases whose etiological agent produce yeast like
cell ,pseudohyphae or septate hyphae in tissues but
certainly contain sclerotic body .

20. EPIDEMOLOGY
• The dematiaceous fungi are widelly present in nature
as contaminant and are not common human
pathogens.
• The fungi are found in soil ,decaying vegetation and
rotten wood.
• These saprotrophic fungi are ubiquitus in nature and
are being recognized with increasing frequency and
cause of human diseases.
• Expanding population of immuno compressed patients
is likely to be responsible due to dematiaceous fungi in
nature.

21. PATHOGENESIS AND PATHOLOGY
• Multiple stellate abscesses progress to single
circumscribed lesion with central cavity filled with pus
and surrounded by fibrous wall.
• The margins of these abscesses and granulomas are
composed of gaint cells , and lymphocytes plasma cells
and lymphocytes .
• The fungi are found in adjacent purulent areas.
• Despite phaeoid nature of causative fungi ,brown
pigment may not always be apparent and hyphae may
also appear hyaline in lesions in H&E.
• GMS (Grocott’s Methenamines Silver stain) marks
natural brown colour of phaeoid hyphae.

22. • There confirmation of presence of these hyphae
can be achieved by using melaning specific stain ,
such as messon - fontana stain .
• In cladophialophora bantiana besides formation
of most common phaeomycotic cyst there may
be pseudoepitheliomatous hyperplasia , mixed
inflammation with granulomatous components
and intraepidermal neutrophilic microabscess
formation.

23. CLINICAL FEATURES
• The fungal agents causing phaeolyphomycosis are
mostly plant pathogens and in soil infecting
subcutaneous tissue by producing solitary lesions.
• These are four clinical types which have been
described on the basis of site of involvement and
degree of tissue invasions by causative fungi.
• The lesions are superficial confined to stratum.
• Cutaneous corneum/corneal- invasion and destruction
of keratinized tissue .
• Subcutaneous and disseminated-generally occuring in
immuno compressed host are associated with high
mortality.

24. • According to phaeoid fungus involved and
anatomical site effected phaeophomycosis
can be classified as follows :
-Cutaneous Phaeohyphomycosis
-Subcutaneous Phaeohyphomycosis
-Invasive and cerebral Phaeohyphomycosis
- Paranasal Sinus Phaeohyphomycosis

25. Fig1:cutaneous phaeohyphomycosis fig2:subcutaneous phaeohyphomycosis

26. Fig1:invasive and cerebral fig2:paranasal sinus phaeohyphomycosis
phaeohyphomycosis

27. LABORATORY DIAGNOSIS
Specimen : pus, biopsy tissue
• Direct microscopic examination :KOH and
smear brown septate hyphae
• Culture on SDA and,it’s very slow growing
black or grey colonies.

29. TREATMENT
• The subcutaneous form of phaeohyphomycosis are
usually treated by local excision but invasive infection
require combination theraphy with intravenous
amphotericin B and oral flucytosine.
• The antifungal drug such as : amphotericin B, flucytosin
ketoconazole, fluconazole , traconazole and terbinatine
have been used with variable success.
• Patient with non life threatening deep seated a
systemic form of phaeohyphomycosis should resceve
traconazole in dose of 200-600 mg per day .