Erythrasma | |
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Specialty | Dermatology |
Causes | Corynebacterium minutissimum |
Erythrasma is a superficial skin infection that causes brown, scaly skin patches. It is caused by Corynebacterium minutissimum bacteria, a normal part of skin flora (the microorganisms that are normally present on the skin).
There are two types of erythrasma: generalized and interdigital. Interdigital is the most common bacterial infection of the feet and normally does not show any symptoms. Not only is this an aesthetically unappealing condition, but there is evidence to support that disciform erythrasma can be an early sign of type 2 diabetes mellitus. The generalized erythrasma is most commonly seen in type 2 diabetes mellitus where the lesions go beyond the areas of the body where skin is rubbing together. [1] It is prevalent among diabetics and the obese, and in warm climates; it is worsened by wearing occlusive clothing.
The presence of erythrasma is approximately 4% and is more likely to be found in the subtropical and tropical areas compared to the rest of the world. It is found more commonly in African Americans due to the darker skin and even though both sexes are affected, it is usually found more frequently in males for the thigh and leg regions. [2] A great contributor to this infection is a weakened immune system which comes with aging, therefore the elderly are more susceptible to this disease than the young; this does not mean the young cannot be affected. The epidemiology background of erythrasma remains partially unsolved.
Lesions of erythrasma are initially pink, but progress quickly to become brown and scaly (as skin starts to shed), which are sharply distinguished. Erythrasmic patches are typically found in moist and intertriginous areas (skin fold areas—e.g. armpit, groin, under breast) and can be well-defined patches or irregular. The most common is interdigital erythrasma, which is of the foot, and may present as a scaling, fissuring, and chronic non-resolving break down of the toe web interspaces. [3] The slightly webbed spaces between toes, or other body region skin folds, make it difficult to distinguish from various Tinea. The patient is commonly otherwise asymptomatic.
Erythrasma is caused by Corynebacterium minutissimum . This bacterium tends to thrive in mostly moist and warm environments. Great contributors are poor hygiene, obesity, hyperhidrosis (excessive sweating), aging, diabetes mellitus, and a poorly functioning immune system. [3] Only some of the causable factors can be modified to reduce risk. Hygiene can be improved, along with avoiding moist and warm environments.
The differential diagnosis for erythrasma includes psoriasis, candidiasis, dermatophytosis, acanthosis nigricans, intertrigo, and many other skin conditions. The diagnosis can be made on the clinical picture alone. However, a simple side-room investigation with a Wood's lamp is additionally useful in diagnosing erythrasma. [4] The ultraviolet light of a Wood's lamp causes the organism to fluoresce a characteristic coral red color, differentiating it from other skin conditions such as tinea versicolor, which may fluoresce a copper-orange color. [5] Another route to differentiate erythrasma would be through bacterial and mycology related cultures to compare/contrast normal results to these findings. These are both non-invasive routes.
Erythrasma is often mistakenly diagnosed as dermatophytic infection which is a fungal infection and not a bacterial infection. The difference here is that fungi are multicellular and eukaryotes while bacteria are single celled prokaryotes. This is vital to differentiate because the way they reproduce will indicate how the infection will spread throughout the human body.
Corynebacterium minutissimum is the bacterium that causes this infection, often club-shaped rods when observed under a microscope following a staining procedure, which is a result of snapping division which makes them look like a picket fence. This bacterium is gram-positive, which means it has a very thick cell wall that cannot be easily penetrated. Electron microscopy confirms the bacterial nature of erythrasma, it shows decreased electron density in keratinized cells at the sites of proliferation. [6] This means that the bacterium causes erythrasma by breaking down keratin Fibrils in the skin. Corynebacterium minutissimum consumes carbohydrates such as glucose, dextrose, sucrose, maltose, and mannitol. [2]
Erythrasma manifests mostly in slightly webbed spaces between toes (or other body region skin folds like the thighs/groin area) in warm atmospheric regions, and is more prevalent in dark skinned humans. As a person ages, they are more susceptible to this infection. This bacterium is not only found in warm atmospheric regions, but also warm and sweaty parts of the human body. Corynebacterium minutissimum survives the best here due to the encouraged fungal growth in these regions and allows it to replicate. It is more prevalent in African Americans due to their skin pigmentation.
Initial treatments for minor erythrasma can begin with keeping the area clean and dry and with antibacterial soaps. The next level is treated with topical fusidic acid and an antibacterial solution such as clindamycin to eradicate the bacteria. For aggressive types of erythrasma, oral antibiotics such as macrolides (erythromycin or azithromycin) can be prescribed. [1] Below is a figure showing the different types and subtypes of therapies.
Oral | Topical |
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Erythromycin | Clindamycin |
Clarithromycin | Whittfield's ointment |
Tetracycline | Sodium fusidate ointment |
Chloramphenicol | Antibacterial soaps |
There is no agreement on the best treatment for this disease. There are many limitations on these treatments such as more irritation, possible allergic reactions, and ulcerations. [3] These treatments are suitable for most ages, but for young children it should be monitored very closely.
Erythrasma has a good prognosis if it is discovered early and properly treated. In more severe cases, it can be an indicator for another disease such as diabetes mellitus.
A blacklight, also called a UV-A light, Wood's lamp, or ultraviolet light, is a lamp that emits long-wave (UV-A) ultraviolet light and very little visible light. One type of lamp has a violet filter material, either on the bulb or in a separate glass filter in the lamp housing, which blocks most visible light and allows through UV, so the lamp has a dim violet glow when operating. Blacklight lamps which have this filter have a lighting industry designation that includes the letters "BLB". This stands for "blacklight blue". A second type of lamp produces ultraviolet but does not have the filter material, so it produces more visible light and has a blue color when operating. These tubes are made for use in "bug zapper" insect traps, and are identified by the industry designation "BL". This stands for "blacklight".
Tinea cruris, also known as jock itch, is a common type of contagious, superficial fungal infection of the groin and buttocks region, which occurs predominantly but not exclusively in men and in hot-humid climates.
Tinea versicolor is a condition characterized by a skin eruption on the trunk and proximal extremities. The majority of tinea versicolor is caused by the fungus Malassezia globosa, although Malassezia furfur is responsible for a small number of cases. These yeasts are normally found on the human skin and become troublesome only under certain conditions, such as a warm and humid environment, although the exact conditions that cause initiation of the disease process are poorly understood.
Athlete's foot, known medically as tinea pedis, is a common skin infection of the feet caused by a fungus. Signs and symptoms often include itching, scaling, cracking and redness. In rare cases the skin may blister. Athlete's foot fungus may infect any part of the foot, but most often grows between the toes. The next most common area is the bottom of the foot. The same fungus may also affect the nails or the hands. It is a member of the group of diseases known as tinea.
A boil, also called a furuncle, is a deep folliculitis, which is an infection of the hair follicle. It is most commonly caused by infection by the bacterium Staphylococcus aureus, resulting in a painful swollen area on the skin caused by an accumulation of pus and dead tissue. Boils are therefore basically pus-filled nodules. Individual boils clustered together are called carbuncles. Most human infections are caused by coagulase-positive S. aureus strains, notable for the bacteria's ability to produce coagulase, an enzyme that can clot blood. Almost any organ system can be infected by S. aureus.
Dermatophyte is a common label for a group of fungus of Arthrodermataceae that commonly causes skin disease in animals and humans. Traditionally, these anamorphic mold genera are: Microsporum, Epidermophyton and Trichophyton. There are about 40 species in these three genera. Species capable of reproducing sexually belong in the teleomorphic genus Arthroderma, of the Ascomycota. As of 2019 a total of nine genera are identified and new phylogenetic taxonomy has been proposed.
Intertrigo, commonly called “skin fold dermatitis”, refers to a type of inflammatory rash (dermatitis) of the superficial skin that occurs within a person's body folds. These areas are more susceptible to irritation and subsequent infection due to factors that promote skin breakdown such as moisture, friction, and exposure to bodily secretions and excreta such as sweat, urine, or feces. Areas of the body which are more likely to be affected by intertrigo include the inframammary fold, intergluteal cleft, armpits, and spaces between the fingers or toes. Skin affected by intertrigo is more prone to infection than intact skin.
Paronychia is an inflammation of the skin around the nail, which can occur suddenly, when it is usually due to the bacterium Staphylococcus aureus, or gradually when it is commonly caused by the fungus Candida albicans. The term is from Greek: παρωνυχία from para 'around', onyx 'nail', and the abstract noun suffix -ia.
Dermatophytosis, also known as tinea and ringworm, is a fungal infection of the skin, that may affect skin, hair, and nails. 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. The types of dermatophytosis are typically named for area of the body that they affect. Multiple areas can be affected at a given time.
Corynebacterium minutissimum is a species of Corynebacterium associated with erythrasma, a type of skin rash. It can be distinguished from similar-appearing rashes by exposing the area to the light of a Wood's lamp; C. minutissimum produces porphyrins that fluoresce coral-red.
Trichobacteriosis axillaris is a superficial bacterial colonization of the hair shafts in sweat gland–bearing areas, such as the armpits and the groin. It is a trivial disease of worldwide occurrence that is believed to be caused by the genus Corynebacteria.
Foot rot, also known as foul-in-the-foot, interdigital necrobacillosis or infectious pododermatitis, is a hoof infection commonly found in sheep, goats, and cattle. As the name suggests, it rots away the foot of the animal, more specifically the area between the two toes of the affected animal. It is extremely painful and contagious. It can be treated with a series of medications, but if not treated, the whole herd can become infected. The cause of the infection in cattle is two species of anaerobic bacteria, Fusobacterium necrophorum and Bacteroides melaninogenicus. Both bacteria are common to the environment in which cattle live, and Fusobacterium is present in the rumen and fecal matter of the cattle. In sheep, F. necrophorum first invades the interdigital skin following damage to the skin, and causes interdigital lesions and slight inflammation. The second stage of the disease is marked by the invasion of the foot by the foot rot bacterium Dichelobacter nodosus, a Gram-negative anaerobe. Usually, an injury to the skin between the hooves allows the bacteria to infect the animal. Another cause of foot rot may be high temperatures or humidity, causing the skin between the hooves to crack and let the bacteria infect the foot. This is one of the reasons foot rot is such a major problem in the summer. Foot rot is easily identifiable by its appearance and foul odor. Treatment is usually with an antibiotic medication, and preventing injury to the feet is the best way to prevent foot rot.
Pitted keratolysis is a bacterial skin infection of the foot. The infection is characterized by craterlike pits on the sole of the feet and toes, particularly weight bearing areas.
Dichelobacter nodosus, formerly Bacteroides nodosus, is a Gram-negative, obligate anaerobe of the family Cardiobacteriaceae. It has polar fimbriae and is the causative agent of ovine foot rot as well as interdigital dermatitis. It is the lone species in the genus Dichelobacter.
Skin flora, also called skin microbiota, refers to microbiota that reside on the skin, typically human skin.
Aquarium granuloma is a rare skin condition caused by a non-tubercular mycobacterium known as Mycobacterium marinum. Skin infections with M. marinum in humans are relatively uncommon, and are usually acquired from contact with contaminated swimming pools, aquariums or infected fish.
Streptococcal intertrigo is a skin condition that is secondary to a streptococcal bacterial infection. It is often seen in infants and young children and can be characterized by a fiery-red color of the skin, foul odor with an absence of satellite lesions, and skin softening in the neck, armpits or folds of the groin. Newborn children and infants commonly develop intertrigo because of physical features such as deep skin folds, short neck, and flexed posture. Prompt diagnosis by a medical professional and treatment with topical and/or oral antibiotics can effectively relieve symptoms.
Foot odor or bromodosis is a type of body odor that affects the feet of humans.
Corynebacterium striatum is a bacterium that is a member of the Corynebacterium genus. It is classified as non-diphtheritic. The bacterium is a gram-positive prokaryote that assumes a 'club-like' morphology, more formally known as a corynebacteria structure. It is non-lipophilic and undergoes aerobic respiration and is also a facultative anaerobe it is catalase negative and oxidase positive glucose and sucrose fermenter.