|
|
|
Fungus Diseases of the skin |
Definition |
Tinea is a group of fungal infections
caused by fungus of different varieties. Particular varieties of fungus
have a preference for specific areas of the body.
The body normally hosts a variety of microorganisms, including bacteria,
mold-like fungi(dermatophytes) and yeast-like fungi (such as
Candida).
Some of these are useful to the body. Others may multiply rapidly and
cause symptoms.
Susceptibility to tinea infection is increased by friction, poor
hygiene, prolonged wetness of the skin such as from sweating, and minor
skin or nail injuries.
|
| Types of tinea: |
| Tinea Capitis: |
Definition:
Tinea capitis is an infection of the scalp by mold-like fungi called
dermatophytes.
Alternative Names:
Fungal infection - scalp Infection - fungal -Tinea of the scalp-Ringworm
of the scalp.
Causes:
Tinea capitis (also called ringworm of the scalp) is a skin disorder
that affects children almost exclusively. It can be persistent and
contagious, almost to the point of epidemic; however, it often
disappears spontaneously at puberty.
The fungi that cause tinea infections thrive in warm, moist areas.
Susceptibility to tinea infection is increased by poor hygiene,
prolonged wetness of the skin (such as from sweating), and minor skin or
scalp injuries.
Tinea infections are contagious and may be passed by direct contact with
affected individuals or by contaminated items such as combs, hats,
clothing, or similar surfaces. They can be transmitted by contact with
pets that carry the fungus, for instance, cats.
|
| Tinea barbae |
Definition:
Tinea barbae is the name used for infection of the beard and moustache
areas of the face with a dermatophytes fungus. It is less common than
tinea capitis and generally affects only adult men.
The cause of tinea barbae is most often a zoophilic (animal) fungus:
T. verrucosum (originating from cattle)
T. mentagrophytes var. equinum (originating from horses)
Tinea barbae is usually due to infection of coarse facial hair with an
ectothrix pattern (spores on the outside). In ectothrix infections, the
fungal filaments (hyphae) and spores (arthroconidia) cover the outside
of the hair.
Clinical Features:
Tinea barbae most often affects farmers and is due to direct contact
with an infected animal. It is rarely passed from one person to another.
Tinea barbae is usually very inflamed with red lumpy areas, pustules and
crusting around the hairs (a kerion), but it is not excessively itchy or
painful. The hairs can be pulled out easily.
Diagnosis:
The diagnosis of tinea barbae is confirmed by microscopy and culture of
skin scrapings and hair pulled out by the roots. |
| Tinea corporis:
|
Definition:
Tinea corporis is an infection of the body surface by mold-like fungi
called dermatophytes.
Alternative Names:
Fungal infection - body Infection - fungal - Tinea of the body- Tinea
circinata-Ringworm of the body.
Causes:
Tinea corporis (often called ringworm of the body) is a common skin
disorder, especially among children, but it may occur in people of all
ages. It is caused by mold-like fungi(dermatophytes) .
Fungi thrive in warm, moist areas. Susceptibility to fungal infection is
increased by poor hygiene, prolonged wetness of the skin (such as from
sweating), and minor skin or nail injuries.
Tinea infections are contagious and can be passed by direct contact with
affected individuals or by contact with contaminated items such as
combs, clothing, shower, or pool surfaces. They can also be transmitted
by contact with pets that carry the fungus (cats are common carriers).
|
| Tinea circinata: |
Definition:
An uncommon morphologic variant of tinea corporis, is caused by the
dermatophytes Tricophyton tonsurans.
Presented as a violaceous plaque consisted of three or four concentric
rings with intervening areas of normal skin and numerous yellow-white
pustules was found on the pretibial surface of the patient's right leg.
At the periphery of the rings, there was fine scaling of the skin.
Diagnosis:
A skin-scraping specimen prepared with potassium hydroxide was evaluated
microscopically and found to contain multiple hyphae. A diagnosis of
tinea circinata was made.
|
 |
| Tinea Pedis (Athlete's foot): |
Definition:
Athlete's foot causes scaling and itching of the affected skin. Blisters
and cracked skin may also occur, leading to exposed raw tissue, pain,
swelling, and inflammation. Despite its name, the infection can be
spread to other areas of the body, such as the armpits, knees, elbows,
and the groin.
The hall mark of these infections is a cherry red color surrounding the
lesion and a yellow thick pus.
Treatment:
The infection is often treated with topical antifungal agents such as
ketoconazole,miconazole, itraconazole, terbinafine and a Keratolytic such as
salicylic acid.
Topical agents only clear the infection about 30% of the time and
provide mycological cures (absence of organisms) less than 15% of the
time. The time line for cure may be long, often 45 days or longer.
However, because the itching associated with the infection subsides
quickly, patients may not complete the courses of therapy prescribed.
Washing socks, underwear and bed clothes at 60°C or 140°F will also help
prevent any reinfection.
Some topical applications such as Castellani's Paint, often used for
Intertrigo, work well but in small selected areas. Carbol Fuscin Red dye
used in this treatment like many other vital stains is both fungicidal
and bactericidal; however, because of the staining are cosmetically
undesirable. For many years gentian violet was also used for
Interdigital and other bacterial and fungal infections.
Oral treatment with
Griseofulvin also used but because of the tendency
to cause liver problems and to provoke a plastic
anemia the drugs were
used cautiously and sparingly. Over time it was found that those
problems were due to the size of the crystal in the manufacturing
process and microsize and now ultramicrosize crystals are available with
few of the original side effects. Oral treatment provides long lasting
mycological cure.
If the fungal invader is not a dermatophytes but a yeast, other
medications such as
fluconazole may be used. Typically
fluconazole is
used for candidal vaginal infections Moniliasis but has been shown to be
of benefit for those with cutaneous yeast infections as well. The most
common of these infections occur in the web spaces (intertriginous) and
at the base of the fingernail or toenail.
|
|
NEXT |
|
|
