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Erythrasma is a superficial skin infection that causes brown, scaly skin patches. It is caused by Corynebacterium minutissimum, 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 Diabetes mellitus type 2 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.

Signs and symptoms[edit]

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 erythrasama, 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 bacteria tends to thrive in mostly moist and warm environments. Great contributors are poor hygiene, obesity, hyperhidrosis, aging, diabetes mellitus, and a poor immune system.[4] Only some of the causable factors can be looked at for prevention. Hygiene can be improved, along with avoiding moist and warm environments. The other medical factors causing the erythrasma are underlying diseases that cannot be prevented as easily, which at times, can make this condition inevitable.


There are differential diagnosis' for erythrasma which includes psoriasis, candidasis, dermaphytosis, and interigo. 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.[5] 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.[6] 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 of the way they reproduce will indicate how the infection will spread throughout the human body.


Corynebacterium minutissimum is the bacteria 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 bacteria 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.[7] This means that the bacteria causes erythrasma by breaking down keratin Fibrils in the skin. Corynebacterium minutissimum consumes carbohydrates such as glucose, dextrose, sucrose, maltose, and mannitol.[8]

Erythrasma manifests mostly in slightly webbed spaces between toes (or other body region skin folds like the thighs/groin area) in warm atmospheric regions, 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.

Treatment and prognosis[edit]

Initial treatments for minor erythrasma can begin with keeping the area clean and dry and with antibacterial soaps. The next level would be treated with topical fusidic acid, miconazole cream, and antibacterial solution such as clindamycin HCL to eradicate the bacteria. For aggressive types of Erythrasma, oral antibiotics like macrolides(erythromycin or azithromycin)can be prescribed.[9] Below is a figure showing the different types and subtypes of therapies.

Oral Topical
Erthromycin Clindamycin
Clarithromycin Whittfield's ointment
Tetracyclin Sodium Fusidate ointment
Chloramphenicol Antibacterial soaps

There is no current agreement on the most optimal treatment for this disease. There are plenty of limitations on these treatments such as more irritation, possible allergic reactions, and ulcerations.[10] These treatments are suitable for most ages, but for young children it should be monitored very closely. Erythrasma if treated and found early on, is not fatal and the patient will live a full life. In more severe cases, it can be an indicator for another disease such as diabetes.

Recent research[edit]

Recent research for Erythrasma is mainly focused on the treatments and which methods work best to treat the patient depending on the severity of the condition. In a 2016 study performed by Prathyusha Prabhakar and H. Hema, they looked into comparing 2% clotrimazole cream and 2% Fusidic cream in treating erythrasma. This was a one year long hospital based study in South India that resulted in stating that the groin was the most common site for the symptoms of itching and discloloration being predominant and also mostly in men. The general conclusion made was that topical 2% fusidic acid cream was found to be more effective than 2% clotrimazole cream in patients with erythrasma. The topical 2% clotrimazole cream was more effective only when an associated fungal infection was present. [11]

Another study performed in early 2017 by Tanya Grewal and Philip Cohen looked directly at mupirocin 2% ointment monotherapy. This study was done with nine males who showed a presence of erythrasma at bilateral inguinal folds, medial thighs, and axillae. After initial diagnosis by Wood lamp's examination to confirm the diagnosis, the antibiotic cream was distributed. Mupirocin is a topical antibiotic that is usually used to treat Streptococcus and Staphylococcus infections. After 2-4 weeks of use, the erythrasma seemed to clear up. They were able to conclude that the application of 2% Mupirocin ointment monotherapy twice a day, everyday is a great consideration for a first line of treatment for erythrasma. [12]

A study done in 2011 by M. Inci and G. Serarslan revolved around detecting the frequency and risk factors of interdigital erythrasma in patients who were possibly diagnosed with Tinea pedis. The study was done with 122 people who had a confirmed diagnoses of erythrasma through the Wood's lamp method. The results showed that erythrasma was more prevalent in males who were over the age of 40 years. Their conclusions were that erythrasma is a common condition and can also easily mimic other infections such as tinea pedis and that gram staining is a better tool to differentiate the bacteria and it's mechanism than the Wood's lamp method.[13]

See also[edit]


  1. ^ "Erythrasma - American Osteopathic College of Dermatology (AOCD)". Retrieved 2017-11-06.
  2. ^ "Erythrasma". Retrieved 2017-11-06.
  3. ^ "Serials Solutions 360 Link". Retrieved 2017-11-06.
  4. ^ "Serials Solutions 360 Link". Retrieved 2017-11-06.
  5. ^ Tony Burns; Stephen Breathnach; Neil Cox; Christopher Griffiths (2010). Rook's Textbook of Dermatology. John Wiley and Sons. pp. 5–. ISBN 978-1-4051-6169-5. Retrieved 14 November 2010.
  6. ^ Likness, LP (June 2011). "Common dermatologic infections in athletes and return-to-play guidelines". The Journal of the American Osteopathic Association. 111 (6): 373–379. PMID 21771922.
  7. ^ "Corynebacterium minutissimum - an overview | ScienceDirect Topics". Retrieved 2017-11-07.
  8. ^ "Erythrasma". Retrieved 2017-11-06.
  9. ^ "Erythrasma - American Osteopathic College of Dermatology (AOCD)". Retrieved 2017-11-06.
  10. ^ "Serials Solutions 360 Link". Retrieved 2017-11-06.
  11. ^ Prabhakar, Prathyusha (2016-09-19). "ERYTHRASMA - A CLINICAL AND A COMPARATIVE STUDY OF TOPICAL 2% CLOTRIMAZOLE CREAM VS TOPICAL 2% FUSIDIC ACID CREAM IN A SEMI-URBAN SETUP IN SOUTH INDIA" (PDF). Archived from the original (PDF) on 2016-09-19. Retrieved 2017-11-06.
  12. ^ Greywal, Tanya (2017-01-01). "Erythrasma: A report of nine men successfully managed with mupirocin 2% ointment monotherapy" (PDF). UC Davis. Archived from the original (PDF) on 2017-01-01. Retrieved 2017-11-06.
  13. ^ Inci, M.; Serarslan, G.; Ozer, B.; Inan, M.u.; Evirgen, O.; Erkaslan Alagoz, G.; Duran, N. (2012-11-01). "The prevalence of interdigital erythrasma in southern region of Turkey". Journal of the European Academy of Dermatology and Venereology. 26 (11): 1372–1376. doi:10.1111/j.1468-3083.2011.04293.x. ISSN 1468-3083.

Further reading[edit]

  • eMedicine
  • Hamann K, Thorn P (1991). "Systemic or local treatment of erythrasma? A comparison between erythromycin tablets and Fucidin cream in general practice". Scand J Prim Health Care. 9 (1): 35–9. doi:10.3109/02813439109026579. PMID 2041927.

External links[edit]

External resources