Subcutaneous mycoses are fungal infections that enter the subcutaneous tissue through the skin. The main types are mycetoma, chromoblastomycosis, sporotrichosis, and rhinosporidiosis. Mycetoma is caused by fungi or bacteria that enter through the feet, causing nodules and sinuses. Chromoblastomycosis causes rough, verrucous skin nodules through fungal implantation. Sporotrichosis is caused by Sporothrix schenckii entering through skin trauma, causing lymphocutaneous nodules. Rhinosporidiosis is caused by Rhinosporidium seeberi, producing polyps in the nose or other mucous membranes

1. Mycology 3
By Dr. Rakesh Prasad Sah
Assistant Professor, Microbiology

2. Subcutaneous MycosesSubcutaneous Mycoses
• These are caused
by fungi that grow
in soil and on
vegetation and are
introduced into
subcutaneous
tissue through

3. Subcutaneous MycosesSubcutaneous Mycoses
1. Mycetoma
2. Chromoblastomycosis
3. Sporotrichosis
4. Rhinosporidiosis

4. • Chronic granulomatous inf of S.T., usually affects
the foot and rarely the other parts of body
• By Gill (1842) from Madurai and Carter (1860)
established the fungal origin of the disease.
• Madura foot or Maduramycosis.
• Distribution
– Tropical countries., quite common in Tamil Nadu.
– First case seen in Madura region of India.
MYCETOMAMYCETOMA
(Maduromycosis=Madura foot)(Maduromycosis=Madura foot)

5. • More seen in rural areas (in farmers, walking
bare-foot in agricultural land or city parks).
• Feet are the most common site for infection
and account for at least two-thirds of cases.
• Other sites include the lower legs, hands,
head, neck, chest, shoulder and arms.

6. Aetiology
• Caused by a number of actinomycetes
and filamentous fungi
• Botryomycosis  Staph aureus
Causative Agent Colour of grains
Eumycetoma
Acremonium falciforme White-yellow
Madurella mycetomi Black
M. grisea Black
Pseudoallescheria boydii White-yellow
Exophiala jeanselmei Black
Actinomycetoma
Actinomadura madurae White-yellow
A. pelletieri Red
Nocardia brasiliensis White
Streptomyces somaliensis Yellow

7. Pathogenesis

13. Laboratory diagnosis:
Clinical specimen:
• Tissue biopsy or excised sinus
• Serosanguinous fluid containing the granules
Methods:
1. Macroscopic examination of the granule
• 0.5 – 2mm diameter
• Actinomycotic mycetoma  Filaments
• Mycotic mycetoma Broader and often
show septae and chlamydospore in

14. Treatment:
• Combining miconazole and surgery may
prove useful in effectively treating the
disease.
• Actinomycotic mycetoma usually respond
well to sulphonamides and antibiotics but
mycotic mycetoma may require
amputation.

15. Chromoblastomycosis -Chromoblastomycosis -
chromomycosischromomycosis
• Slowly progressive granulomatous infection,
characterized by the formation of verrucoid (rough),
warty, cutaneous nodules, which may be raised 1-3 cm
above the skin surface.
• The roughened, irregular, pedunculated vegetations
often resembles the florets of cauliflower.
• Found primarily in the tropics or subtropics

16. Aetiological Agents:
• Fonsecaea pedrosoi
• F. compactum
• Cladosporium carrionii
• Phialophora verrucosa
• These fungi are collectively dematiaceous fungi,
because their conidia or hyphae are dark-colored, either
gray or black.

17. Chromoblastomycosis

18. • Potentially may spread to brain (life-threatening in
that case)

19. Laboratory diagnosis
• Microscopy
• Culture
Specimen: Biopsy tissue
• Hematoxylin stain –
yeast like bodies with septae,
called Sclerotic bodies.
– Colonies of fungi are dark or blackish

20. SporotrichosisSporotrichosis
• Is a nodular, ulcerating ds of
skin & subcutaneous tissue
usually affects hands and
forearms
• Infections are caused by the
traumatic implantation of the
fungus into the skin, or very
rarely, by inhalation into the
lungs.

21. • Through the thorn pricks so most common in gardeners
and farmers.
• May spreads through lymphatics upto regional lymph
nodes and rarely beyond that.
• First case presented with the clinical picture of
sporotrichosis was recorded by Schenck in 1898 from
Johns Hopkins Hospital.

22. • Etiologic agent - Sporothrix schenckii
This fungus is a dimorphic fungus.
At room 25 degree, it grows as a mold producing
branching septate hyphae + conidia & in tissues or
at 37 degree, it grows as small budding yeast cells.
 This fungus lives on plants, grass, trees and rose
thorns.

23. …..Rose gardener’s disease
Sporothrix schenkii infects the body by;
Traumatic
inoculation
Rarely,
inhalation
Lymphocutaneous
sporotrichosis
Pulmonary
lesion
Fixed cutaneous
sporotrichosis

24.  The initial lesion is a granulomatous nodule that will
ulcerate and become necrotic.
 Multiple subcutaneous nodules occur along the
lymphatic vessels.

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29. Lab -diagnosis
• Diagnosis is made by culture
as the fungus may not be
demonstrable in pus or tissues
• 370
C  Yeast
• 220
C-250
C  dimorphic fungus
• Yeast phase appears as cigar-
shaped cells and mould form
contains hyphae carrying
flower like cluster of small
conidia borne on delicate
sterigmata
• Produces progressive ds in
rats on intraperitoneal or
intratesticular inoculation

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32. RhinosporidiosisRhinosporidiosis
• A chronic granulomatous disease
characterised by the production of large
polyps, tumours, papillomas, or wart-like
lesions.
• Usually confined to the nose, mouth or eye
and rarely seen on other mucous membranes.
• Causative agent  Rhinosporidium seeberi
• >80% of cases are from India & Sri Lanka
• MOI is not known but most inf occurs in
males who have frequent contact with
stagnant water or aquatic life.

33. • In tissue, the fungus produces spherules that
possess a thick wall; endospores are contained
within.

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