P5: Subcutaneous Mycoses Flashcards
Chronic localized infections of the skin as well as
the subcutaneous tissue
SUBCUTANEOUS MYCOSES
● Chronic infection of the subcutaneous tissues and
lymphatics
● A fungal infection of the skin caused by a fungus
found on the decaying vegetation, rose bushes or
any plants with thorns, twigs, hays, z
● a.k.a. Rose Gardener’s Disease
SPOROTRICHOSIS
grows well at 35ºC but not at 37ºC
Fixed Cutaneous
causative agent of sporotrichosis
sporothrix schenckii
grows well at 35ºC and 37ºC
Lymphocutaneous
a virulence factor present in lymphocutaneous types
Neuraminidase
○ primary lesion begins as a small,
non-healing ulcer
○ common on index finger or back of the
hand
○ most common form
FIXED CUTANEOUS SPOROTRICHOSIS
infections spreads along the lymph nodes
and a chain of lymphatic nodules develop
in a line
LYMPHOCUTANEOUS SPOROTRICHOSIS
○ with cutaneous lesions on long bones
near affected joints
○ often seen in patients with a history of
alcohol abuse or immunosuppression
OSTEOARTICULAR SPOROTRICHOSIS
○ Rare but can happen when someone
inhales fungal spores from the
environment
■ inhalation of conidia
PULMONARY SPOROTRICHOSIS
clinical manifestations depend on the
organs involved
○ usually affects immunocompromised
individuals
DISSEMINATED SPOROTRICHOSIS
direct examination of subcutaneous mycoses
potassium hydroxide
calcoflour
2 forms of scm
mycelia form (RT)
yeast form (37ºC)
stains used in tissue biopsy
Gomori’s Methenamine Silver
Periodic Acid Schiff
Fluorescent Antibody Testing
H&E
inside are the antigen; outside are the structures covering the antibodies
Splendore-Hoeppli phenomenon
a titer of 1:160 or greater is diagnostic of sporotrichosis
Yeast Cell Agglutination Test
2 types of mycetoma
eumycetoma
actinomycetoma
elicits delayed skin test reactions in sensitive persons
■ major usefulness is in epidemiological investigation
Sporotrichin
most common treatment
amphotericin b
● Chronic infection of the (1) skin including (2)
subcutaneous tissue, and sometimes (3) muscles,
(4) bones, and (5) joint
● Characterized by the presence of nodules
● Usually in lower extremities
MYCETOMA
○ caused by fungal organism
○ fungal mycetoma
EUMYCETOMA
tend to be more aggressive and destructive invading bones; because bacterial agents are able to grow twice or thrice or four times faster than fungal elements
actinomycetoma
○ caused by filamentous bacteria coming
from the order of Actinomycetes
○ bacterial mycetoma
ACTINOMYCETOMA
● Most common cause of eumycetoma WORLDWIDE
Madurella mycetomatis
● Most common agent of mycetoma in US
Scedosporium boydii
(asexual form)
Anamorph
(sexual form)
Teleomorph
● Traumatic inoculation
● Warty, verrucous or cauliflower-like lesions
CHROMOBLASTOMYCOSIS
short flask-shaped phialides with collarette
Phialophora
chains of blastoconidia borne from branching conidiophores
Cladosporium
■ polymorphic; phialides; chains of blastoconidia
■ sympodial: conidia can grow at any part of the phialide or conidiophore
Fonsecaea pedrosoi
○ Produces lateral or terminal conidia from conidiogenous cell
○ elliptical to clavate conidi
Rhinocladiella
■ spherical with broad base connecting the conidia − smaller, more compact (single base only)
Fonsecaea compacta
○ characteristic histologic findings in tissues with chromoblastomycosis ⇒ hallmark
○ copper-colored, septate cells that appear to be dividing (copper pennies)
SCLEROTIC BODIES
A term used to describe subcutaneous and
systemic diseases caused by dematiaceous fungi
other than those causing chromomycosis
PHAEOHYPHOMYCOSIS
● Chronic infection
● Polypoid masses of nasal mucosa
RHINOSPORIDIOSIS
Causative agent of RHINOSPORIDIOSIS
Rhinosporidium seeberi
● Chronic & progressive subcutaneous infection of
humans and dolphins
LOBOMYCOSIS
Causative agent of LOBOMYCOSIS
Loboa loboi
● Initial swelling in the nasal area
● Hard, subcutaneous nodules develop, and an acute
or chronic inflammatory response may ensue
● Severe edema of the nose may block passage of air
RHINOENTOMOPHTHOROMYCOSIS
● Chronic self-limiting infection
● Initial small, firm, movable nodule on the torso or
limb
● Skin is generally intact but may become very rough
SUBCUTANEOUS PHYCOMYCOSIS
Causative agent of RHINOENTOMOPHTHOROMYCOSIS
Entomophthora coronata
causative agent of SUBCUTANEOUS PHYCOMYCOSIS
Basidiobolus haptosporus
