Introduction
Subcutaneous Mycoses
Fungal
infections of the dermis, subcutaneous tissue, and bone, Causative organisms
reside in the soil and decaying or live vegetation. Traumatic implantation with
contaminated material following trauma by a splinter, a thorn, a bite or the
implantation of other foreign bodies. Lesions gradually spread locally without
dissemination to deep organs.
Common causative agents
1. Mycetoma
Mycetoma is
a chronic granulomatous infection of the subcutaneous tissue, usually affects
the foot and rarely other parts of the body. The disease was first described by
gill (1842 ) from Madurai, south India and carter (1860 ) established the
fungal origin of the disease. It is therefore commonly referred to as Madura
foot, or maduromycosis. It occurs mainly in the tropics. The disease is qutite
common in tamilnadu but rare in kerala.
Etiologic agents
The
pathogenic agents are various soil fungi or actinomycetes. Most common are Madurella grisea, Madurella
mycetomatis and Pseudollescheria boydii , Fusarium species, Exophilia species.
Actinomycetes-Actinomyces, Norcardia and Streptomyces. Fungi associated with
fungal mycetoma are opportunistic. Mycotic mycetoma usually more common in men
(3:1 to 5:1) than in women. Usually
results from trauma or puncture wounds to feet, legs, arms and hands (usually
on the feet).
Transmission
Transmission
occurs when the causative organism enters the body through minor trauma or a
penetrating injury, commonly thorn pricks. There is a clear association between
mycetoma and individuals who walk barefooted and are manual workers.
Clinical characteristics of mycetoma
Mycetoma is
characterized by a combination of painless subcutaneous mass, multiple sinuses
and discharge containing grains. It usually spreads to involve the skin, deep
structures and bone, resulting in destruction, deformity and loss of function,
which may be fatal. Mycetoma commonly involves the extremities, back and
gluteal region but any other part of the body can be affected. Secondary
bacterial infection is common, and that may cause increased pain, disability
and fatal septicemia (severe infections involving the entire human system), if
untreated. Infection is not transmitted from human to human. ASuppurative and
granulomatous subcutaneous mycosis. Destructive of contagious bone, tendon and
skeletal muscle The pathogenic agents are various soil fungi or actinomycetes.
Risk factors
Mycetoma
typically presents in: Agricultural
workers (hands, shoulders and back from carrying contaminated vegetation and
other burdens), Individuals who walk barefoot in dry, dusty conditions and
Minor trauma allows pathogens from the soil to enter the skin.
Lab Diagnosis
The
causative organisms can be detected by directly examining the grains that are
discharged by the sinuses, Fine Needle Aspiration (FNA) or surgical biopsy.
Although grains microscopy is helpful in detecting the causative organism,
Identification by Polymerase chain reaction (PCR) is the most reliable method. There
is no serological diagnostic test. In practice, there are no point-of-care
diagnostic tests for use in mycetoma-endemic villages.
Treatment of mycetoma
- There is no effective chemotherapy for fungal mycetoma.
- The treatment is usually surgical excision.
- Actinomycotic mycetoma respond well to sulphonamides and other antibiotics.
Prevention and Control of mycetoma
Mycetoma is
not a notifiable disease (a disease required by law to be reported) and no
surveillance systems exist, and there are no prevention or control programmes
for mycetoma yet. Preventing infection is difficult, but people living in or
travelling to endemic areas should be advised not to walk barefooted.
2. Chromomycosis (Chromo blastomycosis):
Chromomycosis
is a chronic cutaneous and subcutaneous fungal infection, found mainly in
subtropical and tropical areas (in soil and plant debris and transmitted by
traumatic inoculation), and characterized clinically by slow growing, verrucous
nodules, and squamous plaques. Chromomycosis caused by traumatic inoculation of
any of the five dematiaceous fungi: phialophora verrucosa, fonsecaea pedrosoi,
rhinocladiella aquaspersa, fonsecaea capacta, and cladophialophora
carrionii.Recurrent infections results in fibrosis with scar formation causing
lymphatic obstruction (resembles elephantiasis).transmission: the infection
occurs when fungal spores enter the skin through minor trauma, such as thorns,
spinters, or cuts.
Sign and symptom
- Warty nodules that spread slowly
along the lymphatics and develop crusty abscesses.
- Red or violet color on skin may resemble a ringworm lesion.
- Develops into a verrucous (rough) lesion.
- Fungus gets under the skin (produces bumps).
- Bumps may block lymphatic system and cause elephantiasis.
- The lesion is usually painless unless the presence of secondary infection causes itching and pain.
3. Sporotrichosis:
Sporotrichosis
is a disease caused by the infection of the fungus sporothrix schenckii. This
fungal disease usually affects the skin,
although other rare forms can affect the lungs, joints, bones, and even the
brain. Because roses can spread the disease, it is one of few disease referred
to as rosethorn or rose gardeners disease. More common in individuals who have
frequent contact with soil and vegetation and wear little protective clothing.
Sporothrix Schenkii is a Grouped under Ascomycota, The only dimorphic fungus
associated with subcutaneous mycosis Found in soils, plants, decaying
vegetables and other outdoor environments. It has the ability to produce
conidia in its filamentous form.
Symptoms
of the sporotrichosis
The first
symptoms of sporotrichosis is a firm bump on the skin that can range in color
from pink to only mildly tender. Over time, the nodule may develop an open sore
(ulcer) that may drain clear fluid.
What are the complications of sporotrichosis?
- Sporotrichosis is caused by the fungus sporothrix schenkii.
- It often starts as small nodules or ulcers on the skin, particularly on hands or arms.
- Untreated lesion can become chronic, lasting for months or years.
- Chronic lesions increase the risk of secondary bacterial infections.
- Lymphocutaneous spread occurs when the fungus travels along lymphatic vessels.
- This spread results in additional nodules and ulcers, causing swelling and inflammation.
- Disseminated sporotrichosis can invade internal organs, leading to respiratory issues.
Transmission cycle
It infects
both human and animals, both human and animals acquire the pathogen through
traumatic inoculation of the fungus into subcutaneous tissue it affects animals
such as cats, dogs, rats, armadillos and horses. Most human infections acquired from
environments during outdoor occupations or hobbies such as gardening, farming
and hunting etc.
Haw to diagnosis sporotrichosis
Specimens:
The samples to be collected include aspiration fluid, pus biopsy material and
swabs Microscopy: KOHmount of specimen
or histopathological examination tissue sections stained by methanamine silver
stain.
Conclusion
Subcutaneous
mycosis is a chronic fungal infection of the skin and deeper tissues that
develops slowly and needs long-term treatment.
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