Dermatophytosis, also known as ringworm, is a
fungal infection of the
skin
Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation.
Other cuticle, animal coverings, such as the arthropod exoskeleton, have diffe ...
.
Typically it results in a red, itchy, scaly, circular rash.
[ Hair loss may occur in the area affected.][ Symptoms begin four to fourteen days after exposure.][
About 40 types of fungus can cause ringworm.][ They are typically of the '' Trichophyton'', '' Microsporum'', or '' Epidermophyton'' type.][ Risk factors include using public showers, contact sports such as ]wrestling
Wrestling is a series of combat sports involving grappling-type techniques such as clinch fighting, throws and takedowns, joint locks, pins and other grappling holds. Wrestling techniques have been incorporated into martial arts, combat ...
, excessive sweating, contact with animals, obesity
Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it may negatively affect health. People are classified as obese when their body mass index (BMI)—a person's ...
, and poor immune function.[ Ringworm can spread from other animals or between people.][ It may be confirmed by either culturing or looking at a skin scraping under a ]microscope
A microscope () is a laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic means being invisibl ...
.[ Treatment is typically with antifungal creams such as clotrimazole or miconazole.][ If the scalp is involved, antifungals by mouth such as fluconazole may be needed.][ Infections of the scalp are most common in children while infections of the groin are most common in the elderly.]ancient history
Ancient history is a time period from the beginning of writing and recorded human history to as far as late antiquity. The span of recorded history is roughly 5,000 years, beginning with the Sumerian cuneiform script. Ancient history co ...
.
Signs and symptoms
Infection
An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable d ...
s on the body may give rise to typical enlarging raised red rings of ringworm. Infection on the skin of the feet may cause athlete's foot and in the groin, jock itch. Involvement of the nails is termed onychomycosis, and they may thicken, discolour, and finally crumble and fall off. They are common in most adult people, with up to 20% of the population having one of these infections at any given moment.
Animals including dogs and cats can also be affected by ringworm, and the disease can be transmitted between animals and humans, making it a zoonotic disease.
Specific signs can be:
* red, scaly, itchy or raised patches
* patches may be redder on outside edges or resemble a ring
* patches that begin to ooze or develop a blister
* bald patches may develop when the scalp is affected
* nails may thicken, discolour or begin to crack
Causes
Fungi
A fungus (plural, : fungi or funguses) is any member of the group of Eukaryote, eukaryotic organisms that includes microorganisms such as yeasts and Mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified ...
thrive in moist, warm areas, such as locker rooms, tanning bed
Indoor tanning involves using a device that emits ultraviolet radiation to produce a cosmetic tan. Typically found in tanning salons, gyms, spas, hotels, and sporting facilities, and less often in private residences, the most common device is a h ...
s, swimming pool
A swimming pool, swimming bath, wading pool, paddling pool, or simply pool, is a structure designed to hold water to enable Human swimming, swimming or other leisure activities. Pools can be built into the ground (in-ground pools) or built ...
s, and skin folds; accordingly, those that cause dermatophytosis may be spread by using exercise machines that have not been disinfected after use, or by sharing towels, clothing, footwear, or hairbrushes.
Diagnosis
Dermatophyte infections can be readily diagnosed based on the history, physical examination, and potassium hydroxide (KOH) microscopy.
Classification
A number of different species of fungus are involved in dermatophytosis. Dermatophytes of the genera '' Trichophyton'' and '' Microsporum'' are the most common causative agents. These fungi attack various parts of the body and lead to the conditions listed below. The Latin names are for the conditions (disease patterns), not the agents that cause them. The disease patterns below identify the type of fungus that causes them only in the cases listed:
* Dermatophytosis
** Tinea pedis ( athlete's foot): fungal infection of the feet
** Tinea unguium: fungal infection of the fingernails and toenails, and the nail bed
** Tinea corporis: fungal infection of the arms, legs, and trunk
** Tinea cruris ( jock itch): fungal infection of the groin area
** Tinea manuum: fungal infection of the hands and palm area
** Tinea capitis
Tinea capitis (also known as "herpes tonsurans", "ringworm of the hair", "ringworm of the scalp", "scalp ringworm", and "tinea tonsurans") is a cutaneous fungal infection ( dermatophytosis) of the scalp. The disease is primarily caused by dermat ...
: fungal infection of the scalp and hair
** Tinea faciei (face fungus): fungal infection of the face
** Tinea barbae: fungal infestation of facial hair
* Other superficial mycoses (not classic ringworm, since not caused by dermatophytes)
** Tinea versicolor: caused by ''Malassezia furfur
''Malassezia furfur'' (formerly known as ''Pityrosporum ovale'' in its hyphal form) is a species of yeast (a type of fungus) that is naturally found on the skin surfaces of humans and some other mammals. It is associated with a variety of dermato ...
''
** Tinea nigra: caused by '' Hortaea werneckii''
Prevention
Advice often given includes:
* Avoid sharing clothing, sports equipment, towels, or sheets.
* Wash clothes in hot water with fungicidal
Fungicides are biocidal chemical compounds or biological organisms used to kill parasitic fungi or their spores. A fungistatic inhibits their growth. Fungi can cause serious damage in agriculture, resulting in critical losses of yield, quality ...
soap after suspected exposure to ringworm.
* Avoid walking barefoot; instead wear appropriate protective shoes in locker rooms and sandals at the beach.
Vaccination
no approved human vaccine exist against ''Dermatophytosis''. For horses
The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million ...
, dogs
The dog (''Canis familiaris'' or ''Canis lupus familiaris'') is a domesticated descendant of the wolf. Also called the domestic dog, it is derived from the extinct Pleistocene wolf, and the modern wolf is the dog's nearest living relativ ...
and cats
The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of ...
there is available an approved inactivated vaccine called ''Insol Dermatophyton'' ( Boehringer Ingelheim) which provides time-limited protection against several trichophyton and microsporum fungal strains. With cattle, systemic vaccination has achieved effective control of ringworm. Since 1979 a Russian live vaccine (LFT 130) and later on a Czechoslovakian live vaccine against bovine ringworm has been used. In Scandinavian countries vaccination programmes against ringworm are used as a preventive measure
In simple terms, risk is the possibility of something bad happening. Risk involves uncertainty about the effects/implications of an activity with respect to something that humans value (such as health, well-being, wealth, property or the environm ...
to improve the hide quality. In Russia, fur-bearing animals (silver fox, foxes, polar foxes) and rabbits have also been treated with vaccines.
Treatment
Antifungal treatments include topical agents such as miconazole, terbinafine
Terbinafine, sold under the brand name Lamisil among others, is an antifungal medication used to treat pityriasis versicolor, fungal nail infections, and ringworm including jock itch and athlete's foot. It is either taken by mouth or appli ...
, clotrimazole, ketoconazole, or tolnaftate applied twice daily until symptoms resolve — usually within one or two weeks.
History
Dermatophytosis has been prevalent since before 1906, at which time ringworm was treated with compounds of mercury or sometimes sulfur
Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formul ...
or iodine
Iodine is a chemical element with the Symbol (chemistry), symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , ...
. Hairy areas of skin were considered too difficult to treat, so the scalp
The scalp is the anatomical area bordered by the human face at the front, and by the neck at the sides and back.
Structure
The scalp is usually described as having five layers, which can conveniently be remembered as a mnemonic:
* S: The s ...
was treated with X-rays
X-rays (or rarely, ''X-radiation'') are a form of high-energy electromagnetic radiation. In many languages, it is referred to as Röntgen radiation, after the German scientist Wilhelm Conrad Röntgen, who discovered it in 1895 and named it ' ...
and followed up with antifungal medication. Another treatment from around the same time was application of Araroba powder
Araroba powder, also known as Bahia powder and Goa powder, is a drug occurring in the form of a yellowish-brown powder, varying considerably in tint, from the Portugal, Portuguese colony of Goa, where it appears to have been introduced about the ye ...
.
Terminology
The most common term for the infection, "ringworm", is a misnomer, since the condition is caused by fungi
A fungus (plural, : fungi or funguses) is any member of the group of Eukaryote, eukaryotic organisms that includes microorganisms such as yeasts and Mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified ...
of several different species
In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...
and not by parasitic worms.
Other animals
Ringworm caused by '' Trichophyton verrucosum'' is a frequent clinical condition in cattle
Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus '' Bos''. Adult females are referred to as cows and adult ...
. Young animals are more frequently affected. The lesions are located on the head, neck, tail, and perineum
The perineum in humans is the space between the anus and scrotum in the male, or between the anus and the vulva in the female. The perineum is the region of the body between the pubic symphysis (pubic arch) and the coccyx (tail bone), inclu ...
. The typical lesion is a round, whitish crust. Multiple lesions may coalesce in "map-like" appearance.
File:Toplin des dieles tiesse vea.jpg, Multiple lesions, head
File:Dieles åtoû d' l' ouy åmea.JPG, Around the eyes and on ears
File:2 dieles mashale.jpg, On cheeks: crusted lesion (right)
File:Viye diele did près.JPG, Old lesions, with regrowing hair
File:Diele vea waerot.jpg, On neck and withers
File:Dieles cawî åmea.JPG, On perineum
Clinical dermatophytosis is also diagnosed in sheep
Sheep or domestic sheep (''Ovis aries'') are domesticated, ruminant mammals typically kept as livestock. Although the term ''sheep'' can apply to other species in the genus ''Ovis'', in everyday usage it almost always refers to domesticated sh ...
, dogs, cat
The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of ...
s, and horse
The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million ...
s. Causative agents, besides ''Trichophyton verrucosum, are'' ''T. mentagrophytes'', ''T. equinum'', ''Microsporum gypseum'', ''M. canis'', and ''M. nanum''.[
Dermatophytosis may also be present in the ]holotype
A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...
of the Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...
eutriconodont mammal '' Spinolestes'', suggesting a Mesozoic
The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Creta ...
origin for this disease.
Diagnosis
Ringworm in pets may often be asymptomatic, resulting in a carrier condition which infects other pets. In some cases, the disease only appears when the animal develops an immunodeficiency
Immunodeficiency, also known as immunocompromisation, is a state in which the immune system's ability to fight infectious diseases and cancer is compromised or entirely absent. Most cases are acquired ("secondary") due to extrinsic factors that a ...
condition. Circular bare patches on the skin suggest the diagnosis, but no lesion is truly specific to the fungus. Similar patches may result from allergies
Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic derm ...
, sarcoptic mange, and other conditions. Three species of fungi cause 95% of dermatophytosis in pets: these are '' Microsporum canis'', ''Microsporum gypseum
''Microsporum gypseum'' is a soil-associated dermatophyte that occasionally is known to colonise and infect the upper dead layers of the skin of mammals. The name refers to an asexual "form-taxon" that has been associated with four related biolo ...
'', and ''Trichophyton mentagrophytes
''Trichophyton mentagrophytes'' is a species in the fungal genus '' Trichophyton''. It is one of three common fungi which cause ringworm in companion animals. It is also the second-most commonly isolated fungus causing tinea infections in huma ...
''.
Veterinarian
A veterinarian (vet), also known as a veterinary surgeon or veterinary physician, is a medical professional who practices veterinary medicine. They manage a wide range of health conditions and injuries in non-human animals. Along with this, vet ...
s have several tests to identify ringworm infection and identify the fungal species that cause it:
Woods test: This is an ultraviolet light
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiati ...
with a magnifying lens. Only 50% of ''M. canis'' will show up as an apple-green fluorescence on hair shafts, under the UV light. The other fungi do not show. The fluorescent material is not the fungus itself (which does not fluoresce), but rather an excretory product of the fungus which sticks to hairs. Infected skin does not fluoresce.
Microscopic test: The veterinarian takes hairs from around the infected area and places them in a staining solution to view under the microscope. Fungal spores may be viewed directly on hair shafts. This technique identifies a fungal infection in about 40%–70% of the infections, but cannot identify the species of dermatophyte.
Culture test: This is the most effective, but also the most time-consuming, way to determine if ringworm is on a pet. In this test, the veterinarian collects hairs from the pet, or else collects fungal spores from the pet's hair with a toothbrush, or other instrument, and inoculates fungal media for culture. These cultures can be brushed with transparent tape and then read by the veterinarian using a microscope, or can be sent to a pathological lab. The three common types of fungi which commonly cause pet ringworm can be identified by their characteristic spores. These are different-appearing macroconidia
A conidium ( ; ), sometimes termed an asexual chlamydospore or chlamydoconidium (), is an asexual, non- motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also called mitospores due t ...
in the two common species of ''Microspora'', and typical microconidia
A conidium ( ; ), sometimes termed an asexual chlamydospore or chlamydoconidium (), is an asexual, non- motile spore of a fungus. The word ''conidium'' comes from the Ancient Greek word for dust, ('). They are also called mitospores due t ...
in ''Trichophyton'' infections.rodent
Rodents (from Latin , 'to gnaw') are mammals of the Order (biology), order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are roden ...
s, but can also infect pet rabbit
Rabbits, also known as bunnies or bunny rabbits, are small mammals in the family Leporidae (which also contains the hares) of the order Lagomorpha (which also contains the pikas). ''Oryctolagus cuniculus'' includes the European rabbit s ...
s, dogs, and horses. ''M. gypseum'' is a soil organism and is often contracted from gardens and other such places. Besides humans, it may infect rodents, dogs, cats, horses, cattle, and swine.
Treatment
Pet animals
Treatment requires both systemic oral treatment with most of the same drugs used in humans—terbinafine, fluconazole, or itraconazole—as well as a topical "dip" therapy.
Because of the usually longer hair shafts in pets compared to those of humans, the area of infection and possibly all of the longer hair of the pet must be clipped to decrease the load of fungal spores clinging to the pet's hair shafts. However, close shaving is usually not done because nicking the skin facilitates further skin infection.
Twice-weekly bathing of the pet with diluted lime sulfur dip solution is effective in eradicating fungal spores. This must continue for 3 to 8 weeks.
Washing of household hard surfaces with 1:10 household sodium hypochlorite bleach solution is effective in killing spores, but it is too irritating to be used directly on hair and skin.
Pet hair must be rigorously removed from all household surfaces, and then the vacuum cleaner
A vacuum cleaner, also known simply as a vacuum or a hoover, is a device that causes suction in order to remove dirt from floors, upholstery, draperies, and other surfaces. It is generally electrically driven.
The dirt is collected by either a ...
bag, and perhaps even the vacuum cleaner itself, discarded when this has been done repeatedly. Removal of all hair is important, since spores may survive 12 months or even as long as two years on hair clinging to surfaces.
Cattle
In bovine
Bovines (subfamily Bovinae) comprise a diverse group of 10 genera of medium to large-sized ungulates, including cattle, bison, African buffalo, water buffalos, and the four-horned and spiral-horned antelopes. The evolutionary relationship be ...
s, an infestation is difficult to cure, as systemic treatment is uneconomical. Local treatment with iodine
Iodine is a chemical element with the Symbol (chemistry), symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , ...
compounds is time-consuming, as it needs scraping of crusty lesions. Moreover, it must be carefully conducted using glove
A glove is a garment covering the hand. Gloves usually have separate sheaths or openings for each finger and the thumb.
If there is an opening but no (or a short) covering sheath for each finger they are called fingerless gloves. Fingerless glo ...
s, lest the worker become infested.
Epidemiology
Worldwide, superficial fungal infections caused by dermatophytes are estimated to infect around 20-25% of the population and it is thought that dermatophytes infect 10-15% of the population during their lifetime.[Pires, C. A. A., Cruz, N. F. S. da, Lobato, A. M., Sousa, P. O. de, Carneiro, F. R. O., & Mendes, A. M. D. (2014). Clinical, epidemiological, and therapeutic profile of dermatophytosis. ''Anais Brasileiros de Dermatología'', ''89''(2), 259–264]
/ref>[Oumar Coulibaly, Coralie L'Ollivier, Renaud Piarroux, Stéphane Ranque, Epidemiology of human dermatophytoses in Africa, ''Medical Mycology'', Volume 56, Issue 2, February 2018, Pages 145–161.] The highest Incidence (epidemiology), incidence of superficial mycoses result from dermatophytoses which are most prevalent
In epidemiology, prevalence is the proportion of a particular population found to be affected by a medical condition (typically a disease or a risk factor such as smoking or seatbelt use) at a specific time. It is derived by comparing the number o ...
in tropical regions.[Rajagopalan, M., Inamadar, A., Mittal, A., Miskeen, A. K., Srinivas, C. R., Sardana, K., Godse, K., Patel, K., Rengasamy, M., Rudramurthy, S., & Dogra, S. (2018). Expert Consensus on The Management of Dermatophytosis in India (ECTODERM India). ''BMC dermatology'', ''18''(1), 6]
/ref> Onychomycosis, a common infection caused by dermatophytes, is found with varying prevalence rates in many countries.[Hayette, M.-P., & Sacheli, R. (2015). Dermatophytosis, Trends in Epidemiology and Diagnostic Approach. ''Current Fungal Infection Reports'', ''9''(3), 164–179]
/ref> ''Tinea pedis'' + onychomycosis, ''Tinea corporis'', ''Tinea capitis'' are the most common dermatophytosis found in humans across the world.epidemic
An epidemic (from Greek ἐπί ''epi'' "upon or above" and δῆμος ''demos'' "people") is the rapid spread of disease to a large number of patients among a given population within an area in a short period of time.
Epidemics of infectious d ...
s throughout Europe and America.[Gordon, E., Idle, A., & DeTar, L. (2020). Descriptive epidemiology of companion animal dermatophytosis in a Canadian Pacific Northwest animal shelter system. ''The Canadian veterinary journal = La revue veterinaire canadienne'', ''61''(7), 763–770.] Pets are susceptible to dermatophytoses caused by ''Microsporum canis'', ''Microsporum gypseum'', and ''Trichophyton''.socioeconomic status
Socioeconomic status (SES) is an economic and sociological combined total measure of a person's work experience and of an individual's or family's economic access to resources and social position in relation to others. When analyzing a family's ...
was found to be a risk factor for ''Tinea capitis''.Trichophyton rubrum
''Trichophyton rubrum'' is a dermatophytic fungus in the phylum Ascomycota. It is an exclusively clonal, anthropophilic saprotroph that colonizes the upper layers of dead skin, and is the most common cause of athlete's foot, fungal infection of n ...
'' (49.4%), followed by ''Trichophyton mentagrophytes'' (30.8%), and ''Microsporum canis'' (12.6%).
A 2013 study looking at 5,175 samples of ''Tinea'' in patients in Tehran, Iran found the most prevalent type to be ''Tinea pedis'' (43.4%), followed by ''Tinea unguium''. (21.3%), and ''Tinea cruris'' (20.7%).[Rezaei-Matehkolaei, A., Makimura, K., de Hoog, S., Shidfar, M. R., Zaini, F., Eshraghian, M., Naghan, P. A., & Mirhendi, H. (2013). Molecular epidemiology of dermatophytosis in Tehran, Iran, a clinical and microbial survey. ''Medical Mycology (Oxford)'', ''51''(2), 203–207]
/ref>
See also
* Mycobiota (human), Mycobiota
References
Further reading
*
External links
Tinea photo library at Dermnet
{{Authority control
Animal fungal diseases
Mycosis-related cutaneous conditions
Wikipedia medicine articles ready to translate
Cat diseases
Wikipedia emergency medicine articles ready to translate