Mycosis
Encyclopedia
A mycosis is a fungal infection
Infection
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...

 of animals, including humans. Mycoses are common, and a variety of environmental and physiological conditions can contribute to the development of fungal diseases. Inhalation of fungal spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...

s or localized colonization of the skin
Skin
-Dermis:The dermis is the layer of skin beneath the epidermis that consists of connective tissue and cushions the body from stress and strain. The dermis is tightly connected to the epidermis by a basement membrane. It also harbors many Mechanoreceptors that provide the sense of touch and heat...

 may initiate persistent infections; therefore, mycoses often start in the lungs or on the skin.

Causes

People are at risk of fungal infections when they are taking strong antibiotics for a long period of time because antibiotics kill not only damaging bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...

, but healthy bacteria as well. This alters the balance of microorganisms in the mouth
Mouth
The mouth is the first portion of the alimentary canal that receives food andsaliva. The oral mucosa is the mucous membrane epithelium lining the inside of the mouth....

, vagina
Vagina
The vagina is a fibromuscular tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. Female insects and other invertebrates also have a vagina, which is the terminal part of the...

, intestines and other places in the body, and results in an overgrowth of fungus.

Individuals with weakened immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...

s are also at risk of developing fungal infections. This is the case of people with HIV
HIV
Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...

/AIDS
AIDS
Acquired immune deficiency syndrome or acquired immunodeficiency syndrome is a disease of the human immune system caused by the human immunodeficiency virus...

, people under steroid
Steroid
A steroid is a type of organic compound that contains a characteristic arrangement of four cycloalkane rings that are joined to each other. Examples of steroids include the dietary fat cholesterol, the sex hormones estradiol and testosterone, and the anti-inflammatory drug dexamethasone.The core...

 treatments, and people taking chemotherapy
Chemotherapy
Chemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....

. People with diabetes also tend to develop fungal infections. Very young and very old people, also, are groups at risk.

Classification

Mycoses are classified according to the tissue
Biological tissue
Tissue is a cellular organizational level intermediate between cells and a complete organism. A tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function. These are called tissues because of their identical functioning...

 levels initially colonized.

Superficial mycoses

Superficial mycoses are limited to the outermost layers of the skin and hair.

An example of a fungal infection is Tinea versicolor
Tinea versicolor
Tinea versicolor is a condition characterized by a rash on the trunk and proximal extremities. Recent research has shown that the majority of Tinea versicolor is caused by the Malassezia globosa fungus, although Malassezia furfur is responsible for a small number of cases...

, a fungus infection that commonly affects the skin of young people, especially the chest, back, and upper arms and legs. Tinea versicolor is caused by a fungus that lives in the skin of some adults. It doesn't usually affect the face. This fungus produces spots that are either lighter than the skin or a reddish-brown. This fungus exists in two forms, one of them causing visible spots. Factors that can cause the fungus to become more visible include high humidity, as well as immune or hormone abnormalities. However, almost all people with this very common condition are healthy.

Cutaneous mycoses

Cutaneous mycoses extend deeper into the epidermis, and also include invasive hair and nail diseases. These diseases are restricted to the keratinized layers of the skin, hair, and nails. Unlike the superficial mycoses, host immune responses may be evoked, resulting in pathologic changes expressed in the deeper layers of the skin. The organisms that cause these diseases are called dermatophyte
Dermatophyte
Dermatophytes are a common label for a group of three types of fungus that commonly causes skin disease in animals and humans. These anamorphic genera are: Microsporum, Epidermophyton and Trichophyton. There are about 40 species in these three genera...

s. The resulting diseases are often called ringworm (even though there is no worm involved) or tinea
Tinea
Tinea is a general term used to describe skin mycoses. The term ringworm is even less precise, but is usually considered a synonym.It is sometimes equated with dermatophytosis, and it is true that most conditions identified as "tinea" are members of the imperfect fungi that make up the dermatophytes...

. Cutaneous mycoses are caused by Microsporum
Microsporum
Microsporum is a genus of fungi that causes tinea capitis, tinea corpus, ringworm, and other dermatophytoses. Microsporum forms both macroconidia and microconidia on short conidiophores...

, Trichophyton
Trichophyton
The fungus genus Trichophyton is characterized by the development of both smooth-walled macro- and microconidia. Macroconidia are mostly borne laterally directly on the hyphae or on short pedicels, and are thin- or thick-walled, clavate to fusiform, and range from 4 to 8 by 8 to 50 um in size....

, and Epidermophyton
Epidermophyton
Epidermophyton is a genus of fungus causing superficial and cutaneous mycoses, including E. floccosum, a cause of tinea corporis , tinea cruris , tinea pedis , and onychomycosis or tinea unguium, a fungal infection of the nail bed.-External links:**...

fungi, which together comprise 41 species.

One common disease is the athlete's foot
Athlete's foot
Athlete's foot is a fungal infection of the skin that causes scaling, flaking, and itch of affected areas. It is caused by fungi in the genus Trichophyton and is typically transmitted in moist areas where people walk barefoot, such as showers or bathhouses...

 which most commonly affects men and children before puberty
Puberty
Puberty is the process of physical changes by which a child's body matures into an adult body capable of reproduction, as initiated by hormonal signals from the brain to the gonads; the ovaries in a girl, the testes in a boy...

. It is divided in three categories: chronic interdigital athlete's foot, chronic scaly athlete's foot, and acute vesicular athlete's foot.

Subcutaneous mycoses

Subcutaneous mycoses involve the dermis, subcutaneous tissues, muscle, and fascia. These infections are chronic and can be initiated by piercing trauma to the skin, which allows the fungi to enter. These infections are difficult to treat and may require surgical interventions such as debridement
Debridement
Debridement is the medical removal of a patient's dead, damaged, or infected tissue to improve the healing potential of the remaining healthy tissue...

.

Systemic mycoses due to primary pathogens

Systemic mycoses due to primary pathogens originate primarily in the lung
Lung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...

s and may spread to many organ systems. Organisms that cause systemic mycoses are inherently virulent. Generally, primary pathogens that cause systemic mycoses are dimorphic.

Systemic mycoses due to opportunistic pathogens

Systemic mycoses due to opportunistic pathogens are infections of patients with immune deficiencies who would otherwise not be infected. Examples of immunocompromised conditions include AIDS
AIDS
Acquired immune deficiency syndrome or acquired immunodeficiency syndrome is a disease of the human immune system caused by the human immunodeficiency virus...

, alteration of normal flora by antibiotics, immunosuppressive therapy, and metastatic cancer. Examples of opportunistic mycoses include Candidiasis
Candidiasis
Thrush redirects here. For the hoof infection see Thrush .Candidiasis or thrush is a fungal infection of any of the Candida species , of which Candida albicans is the most common...

, Cryptococcosis
Cryptococcosis
Cryptococcosis, or cryptococcal disease, is a potentially fatal fungal disease. It is caused by one of two species; Cryptococcus neoformans and Cryptococcus gattii. These were all previously thought to be subspecies of C...

 and Aspergillosis
Aspergillosis
Aspergillosis is the name given to a wide variety of diseases caused by fungi of the genus Aspergillus. The most common forms are allergic bronchopulmonary aspergillosis, pulmonary aspergilloma and invasive aspergillosis. Most humans inhale Aspergillus spores every day...

.

Treatment

Antifungal drug
Antifungal drug
An antifungal medication is a medication used to treat fungal infections such as athlete's foot, ringworm, candidiasis , serious systemic infections such as cryptococcal meningitis, and others...

s are used to treat mycoses. Depending on the nature of the infection, a topical or systemic agent may be used. Photochemotherapy or photopheresis
Photopheresis
In medicine, photopheresis or extracorporeal photopheresis is a form of apheresis and photodynamic therapy in which blood is treated with photoactivable drugs which are then activated with ultraviolet light....

 is a technique used at medical centers for the treatment of mycosis fungoides.

An example of antifugal is fluconazole
Fluconazole
Fluconazole is a triazole antifungal drug used in the treatment and prevention of superficial and systemic fungal infections. In a bulk powder form, it appears as a white crystalline powder, and it is very slightly soluble in water and soluble in alcohol. It is commonly marketed under the trade...

, or Diflucan, which is the basis of many over-the-counter antifungal treatments. Another example is amphotericin B
Amphotericin B
Amphotericin B is a polyene antifungal drug, often used intravenously for systemic fungal infections...

 (the A form being toxic) which is more potent. It is used in the treatment of the most severe fungal infections that show resistance to other forms of treatment and it is administered intravenously.

Drugs to treat skin infections are Tolnaftate (Tinactin), an over the counter topical; Ketoconazole
Ketoconazole
Ketoconazole is a synthetic antifungal drug used to prevent and treat fungal skin infections, especially in immunocompromised patients such as those with AIDS or those on chemotherapy. Ketoconazole is sold commercially as an anti-dandruff shampoo, topical cream, and oral tablet.Ketoconazole is...

, especially used to treat tinea versicolor and other dermatophytes; Itraconazole
Itraconazole
Itraconazole , invented in 1984, is a triazole antifungal agent that is prescribed to patients with fungal infections. The drug may be given orally or intravenously.-Medical uses:...

; Terbinafine (Lamisil); Echinocandins (caspofungin); Griseofulvin
Griseofulvin
Griseofulvin is an antifungal drug that is administered orally. It is used both in animals and in humans, to treat fungal infections of the skin and nails...

, commonly used for infections involving the scalp and nails.

Yeast infections in the vagina, caused by candida albicans
Candida albicans
Candida albicans is a diploid fungus that grows both as yeast and filamentous cells and a causal agent of opportunistic oral and genital infections in humans. Systemic fungal infections including those by C...

, can be treated with medicated suppositories whereas skin yeast infections are treated with medicated ointments.

Prevention

Keeping the skin clean and dry, as well as maintaining good hygiene
Hygiene
Hygiene refers to the set of practices perceived by a community to be associated with the preservation of health and healthy living. While in modern medical sciences there is a set of standards of hygiene recommended for different situations, what is considered hygienic or not can vary between...

, will help larger topical mycoses. Because fungal infections are contagious, it is important to wash after touching other people or animals. Sports clothing should also be washed after use. Wearing flip-flops if using a community swimming pool
Swimming pool
A swimming pool, swimming bath, wading pool, or simply a pool, is a container filled with water intended for swimming or water-based recreation. There are many standard sizes; the largest is the Olympic-size swimming pool...

 or shower
Shower
A shower is an area in which one bathes underneath a spray of water.- History :...

will also help prevent topical infections.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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