Subcutaneous Mycoses Flashcards
Causative agents of:
Chromoblastomycosis
Chromomycosis
Dematiaceous fungi
(having melanin or melanin-like pigment in the wall of their hyphae and/or spores)
✅ Phialophora verrucosa
✅ Fonseccae pedrosoi
✅ Rhinocladiella aquaspersa
✅ Fonseccae compactum
✅ Cladophialophora carrionii
Mycetoma causative agents
🩵Pseuddallescheria boydii
🩵Acremonium falciforme
🩵Madurella mycetomatis
🩵M. Grisea
🩵Exophiala jeanselmi
Sporotrichosis causative agent
Sporothrix schenkii
Rhinosporidiosis causative agent
Rhinosporidium seeberi
Phaeohyphomycosis causative agents
🩵 Exophiala spp
🩵 E. dermatitidis
Lobomycosis causative agent
Lacazia loboi
Chronic, slowly progressive granulomatous infection of skin & subcutaneous tissues with the involvement of underlying fascia & bones commonly affecting the extremities.
MYCETOMA
AKA Maduramycosis or Madura foot.
MYCETOMA
Two (2) Classification of Mycetoma
̈ Based on the causative agent
̈ Based on the colour of grains
Colour of grains in Mycetoma of various etiology
White to yellow
Brown to black
Red
Brown to black mycetoma
Madurella mycetomatis
Madurella grisea
Exophiala jeanselmei
White to yellow grains Mycetoma
Pseudollescheria boydii
Acremonium falciforme
Red grains mycetoma
Actinomadura madurai
Common among field workers, famers - prone to thorn prick injury & trauma.
Mycetoma
NOTE:
🩵Entry of pathogen into the injured site, mostly foot.
🩵Formation of multiple sinuses on the surface discharging viscid, seropurulent fluid containing granules or grains which are microcolonies of the causative agent.
🐈
Mycetoma Triad
🩵Tumefaction - tumor like swelling
🩵Multiple draining sinuses
🩵Presence of grains or granules in sinuses.
Under microscopy on direct examination using KOH mount. A 2-6μ, wide interwoven hyphae with large, swollen cells (chlamydospores) at the margin of the lesion was seen.
What disease can the causative agent cause?
Mycetoma
SPOROTRICHOSIS causative agent
- Associated with a variety of plants grasses, trees, sphagnum
moss, rose bushes
Sporothrix schenckii ( a dimorphic fungi)
Caused by thorn pricks or other minor injuries. ̈ Mostly involves upper limbs
SPOROTRICHOSIS
Pathogenesis & pathology: Give the causative agent and associated disease
– Clinical features - Nodules on the skin, subcutaneous tissue and in the LNs which later soften & ulcerate.
– Pyogranulomatous reaction
– Elicit delayed skin test – “sporotrichin”
Lymphocutaneous sporotrichosis
🩵 Sporothicosis infection
🩵 Sporothrix schenckii
Direct Examination
- organisms appear as cigar shaped bodies (yeast cells) 3-5μ in diameter.
🩵 Sporothicosis infection
🩵 Sporothrix schenckii
Appears as “Asteroid bodies” in the lesion: central fungus cell surrounded by a refractile eosinophilic halo, called?
“ Splendore-Hoeppli” phenomenon
- due to immune complex deposition around the rganism.
Note:
🧫Sprotrichosis: Culture
̈ Inoculated on 2 sets of SDA, BHIA
̈ Incubated at 25°& 37°C ̈ Smear from Culture
— septate hyphae - very thin & carry flower like clusters of small conidia on delicate sterigmata
🩵
RHINOSPORIDIOSIS causative agent
Rhinosporidium seeberi
High incidence among people who frequently bath along with domestic animals in ponds, tanks, lakes
RHINOSPORIDIOSIS caused by Rhinosporidium seeberi
🐈 Characterised by the development of friable polyps in the nose, mouth or eye.
🐈 Chronic, recurrent granulomatous disease of mucous membrane.
-Miscellaneous forms – Buccal cavity,vagina, vulva, penis, urethra
or rectum
RHINOSPORIDIOSIS caused by Rhinosporidium seeberi
Direct Examination for Rhinosporidium seeberi (cannot be cultured)
🐈FNAC,
🐈Biopsy of lesion
🐈Nasal washing
Rhinosporidiosis: Treatment & Prophylaxis
🐈Radical Surgery:- Excision/ Electrocautery
̈ Medical therapy :- not useful
(Recurrences common)
