There are two forms of erythrasma: 1) interdigital and 2) generalized.

Interdigital erythrasma is more common than the generalized variant. It frequently appears on the 3rd and 4th web spaces of the foot, especially the 4th interdigital space [5]. The main characteristics of the lesions are maceration, scaling, and fissuring. These patients usually remain overall asymptomatic. Erythrasma may affect other areas such as the axillae, groin, and perineum. Furthermore, it targets moist regions such as infra breast, abdominal and intergluteal folds. Diabetics and obese women are particularly prone to infection in these areas.

At the onset of erythrasma, skin lesions are well demarcated pink-red scaly patches giving a wrinkled characteristic. They transform into brown-red macular patches and hence, this discoloration is observed in moist body folds. While the infection does not usually manifest in other symptoms, pruritus can occur. Erythrasma lasts from months to years. Some cases involve body-wide distribution such as the trunk and extremities.

Generalized erythrasma is more frequently observed in type 2 diabetics but can also occur in nondiabetics. Lesions extend beyond body folds. They are described as well-circumscribed erythematous patches that may be scaly or smooth. This type of infection is usually pruritic. Since these lesions may be confused with cutaneous dermatophytosis, potassium hydroxide preparation is used to differentiate these two.

Patients with recurrent episodes should be evaluated for diabetes. In fact, identifying and modifying this risk factor is important to prevent recurrence. Of importance, immunosuppressed individuals are susceptible to complications. Patients with erythrasma can also have concomitant infections with other organisms. These must be treated as well. Atypical cases are common and tend to appear with color variations. 

A careful exam of both feet and all body folds can differentiate erythrasma from other corynebacterial skin infections such as pitted keratolysis and trichomycosis axillaris. The clinical presentation of erythrasma is similar to that of tinea and intertrigo. An appropriate work up is key. 

• Candidiasis

  Tinea versicolor and candidiasis were observed in 10 (12.5%) and 6 (7.5%) cases, respectively (Table 1). [ncbi.nlm.nih.gov]

  The differential diagnosis of erythrasma includes psoriasis, dermatophytosis, candidiasis, and intertrigo. [aafp.org]

  The differential diagnosis of erythrasma includes psoriasis, dermatophytosis, candidiasis and intertrigo, and methods for differentiating include Wood’s light examination and bacterial and mycological cultures. [doi.org]

  The differential diagnosis of erythrasma includes other causes of axillary erythema such as candidiasis, tinea corporis, and contact dermatitis. ↑ back to top In proceeding with payment you agree to purchase a one-time PDF download of the selected JDDonline [jddonline.com]

  The clinical presentation of erythrasma can resemble candidiasis, dermatophyte infections, pityriasis versicolor, and terra firma-forme dermatosis [1, 2]. [cureus.com]

• Inflammation

  Pigmented lesions with limited itching and lack of crusting, marginality, satellite lesions and inflammation could be a lead to tinea versicolor and skin lesions without any inflammation, itching, marginality, satellite lesions with pigmentation (red [ncbi.nlm.nih.gov]

  [G. erythrainō, to redden] erythrasma superficial infection of intertriginous skin (e.g. interdigital spaces of feet) caused by Corynebacterium minutissimum ; characterized by local chronic inflammation, skin discoloration (initially red, but later brown [medical-dictionary.thefreedictionary.com]

  Erosio interdigitalis blastomycetica: A review of interdigital candidiasis. 61 Schlager E...Khachemoune A 30677843 2018 10 Skin diseases of the vulva: Infectious diseases. 61 Sand FL...Thomsen SF 28397528 2017 11 Influence of low-level laser on pain and inflammation [malacards.org]

  There is no inflammation associated with this. It usually does not produce any symptoms. Treatment: Usually drying the skin with anti-perspirants can be very beneficial Topical antibiotics can also be of benefit. [skintherapyletter.com]

  Erythromycin, Clarithromycin and Miconazole are prescribed for controlling infection and inflammation. Some complications may arise for patients with low immunity and those who have surgical wounds when they are infected with Erythrasma. [health9.org]

• Sepsis

  […] carcinoma of the breast + Extramammary Paget's disease + Epidermal spread of colonic adenocarcinoma + Bacterial, mycotic and parazitic diseases; viruses + Bacterial inflammations with suppuration, pyodermia + Erosive pustulosis of the head + Erysipelas + Sepsis [atlases.muni.cz]

  […] minutissimum in an HIV-infected patient, J Infect, 2000, vol. 41 (pg. 103 - 5 ) 4 Central venous catheter–;related Corynebacterium minutissimum bacteremia, Infect Control Hosp Epidemiol, 1998, vol. 19 (pg. 786 - 9 ) 5 Polymicrobial central venous catheter sepsis [cid.oxfordjournals.org]

  Sepsis may occur in persons with diabetes and in immunocompromised persons, and hospital admission should be considered for such patients, as well as for any patient with significant systemic signs and symptoms. [aafp.org]

• Chronic Infection

  Erythrasma This is a superficial chronic infection caused by a bacteria called Corynebacterium minutissimus. It is most commonly seen in the groin, armpits and in the folds. [skintherapyletter.com]

  Chronic infection is seen more frequently when moisture, obesity, and underlying diseases, such as diabetes, exist.1,2 Porphyrin production is responsible for the characteristic coral red fluorescence under Wood light and is clinically useful. [jamanetwork.com]

• Sweating

  Also read: How to Get Rid of Heat Bumps or Rashes Night Sweats in Men: Causes and Natural Treatments Cold Sweats: Causes and Symptoms How to Stop Excessive Sweating (Hyperhidrosis): Causes and Treatment [doctorshealthpress.com]

  An important factor in the prevention of erythrasma is to prevent sweating. You must wear clothes made of natural fabrics, use deodorant sweat, as well as to monitor the hygiene of skin folds. [noillen.netlify.com]

  If you live in a hot and humid climate, wear light and loose cotton clothing to help with sweating. This will wick the sweat off your body. Try to stay in cool areas or in the shade. Keep your house temperature cool too. Baby powder. [webmd.com]

  The below conditions can predispose individuals to erythrasma: Obesity Diabetes Poor hygiene Excessive sweating Immune deficiency Erythrasma Treatment Your primary care physician can normally diagnosis erythrasma by looking at the area. [byebyedoctor.com]

• Intertrigo

  Risk Factors Similar to risks associated with Intertrigo III. Symptoms Usually asymptomatic May be pruritic in some cases IV. [fpnotebook.com]

  Intertrigo has a spectrum of infectious and non-infectious causes (5). Skin fungal infections are among the major causes of intertrigo and affect a large scale of people worldwide (6). [ncbi.nlm.nih.gov]

  Intertrigo and secondary skin infections. Am Fam Physician. 2014; 89 (7): p.569-73. [amboss.com]

  Compare intertrigo, tinea cruris. erythrasma infectious disease A patchy red-brown rash in the axilla and inguinal region, due to the presence of Corynebacterium minutissimum in the stratum corneum er·y·thras·ma ( er'i-thraz'mă ) An eruption of well-circumscribed [medical-dictionary.thefreedictionary.com]

• Dermatitis

  acute + Dyshidrotic dermatitis + Eczema atopicum (dermatitis atopica) + Subacute and chronic (eczem) dermatitis + Microbial eczema + Granuloma gluteale infantum + Toxic contact (irritative) dermatitis, acute + Toxic contact (irritative) dermatitis, [atlases.muni.cz]

  Contact dermatitis Tinea versicolor Confluent and reticulated papillomatosis Tinea pedis (differential of web space erythrasma) May present as granulomatous plaques in immunocompromised patients. [visualdx.com]

  Differential Diagnosis (Other conditions with similar appearance) Acanthosis Nigricans Seborrheic Dermatitis Candidiasis Tinea Infection Contact Dermatitis Intertrigo Psoriasis Diagnosis Key Points *Diagnosis based on UV light testing *Microscopy and [ozarkderm.com]

  References:[2] Diagnostics Differential diagnoses Intertrigo (intertriginous dermatitis) [4] Definition: dermatitis that particularly affects skin folds (submammary, inguinal, interdigital) Etiology Increased moisture in the skin folds (e.g., aggravated [amboss.com]

  Keywords Normal Flora Tinea Pedis Seborrheic Dermatitis Tinea Cruris Direct Microscopic Examination These keywords were added by machine and not by the authors. [link.springer.com]

• Hyperhidrosis

  Factors such as a warm climate, poor hygiene, obesity, hyperhidrosis, advanced age, compromised host status, and diabetes mellitus also play a role in the occurrence of this organism. [aafp.org]

  Factors such as obesity, hyperhidrosis, and poor hygiene favor its development. The characteristic ”coral red” fluorescence of erythrasma is caused by coproporphyrin III produced by Corynebacterium minutissimum. [jddonline.com]

  Risk Factors Obesity Diabetes Occlusive clothing/shoes Hyperhidrosis Immunocompromised state Advanced age Living in a subtropical or tropical region General Prevention Nonocclusive clothing and footwear Good hygiene Weight loss Good blood sugar control [unboundmedicine.com]

  Even low immunity and hyperhidrosis is known to cause this sort of infection. Common symptoms of Erythrasma Erythrasma shows unmistakable symptoms. It looks like a patch of pink to red skin with a well-defined border. [lybrate.com]

  Hyperhidrosis. Poor hygiene. Advanced age. Erythrasma is a sharply delineated, dry, red-brown patch with slightly scaling patches. Some lesions appear redder, whereas others have a browner color (Figures 119-3 and 119-4). [accessmedicine.mhmedical.com]

• Papule

  Clinical features Erythematous papules/plaques → macerations, crusting, erosion, or fissures on an erythematous base In addition, if infected with Candida: satellite lesions Diagnosis: Secondary infections can be confirmed with microbiological testing [amboss.com]

  Larger, disfiguring hemangiomas and darker, flat macules or papules also may develop. The small bowel is the most commonly affected site; however, any part of the GI tract can be involved. Blebs in the colon most often are located distally. [consultant360.com]

  Rothmund Thomson + Poikiloderma vasculare atrophicans + Infiltration of the upper and deep corium + Erythema annulare centrifugum (erythema figuratum) + Erythema gyratum repens + Lymphocytic infiltrate of Jessner-Kanof + Urticaria + Pruritic urticarial papules [atlases.muni.cz]

  –Candidiasis: Bright erythematous plaques and papules with satellite lesion and positive KOH examination demonstrating pseudohyphae and buds. [dermatologyadvisor.com]

• Confusion

  Note: Erythrasma is often confused with a fungal infection, such as tinea cruris, but this confusion is of little consequence since corynebacteria are often eradicated with an imidazole cream (such as Miconazole and others), the agent used to treat tinea [skincarenet.org]

  Interdigital erythrasma is the most common form and is easily confused with tinea pedis. The aim of this study was to determine the prevalence of interdigital erythrasma in patients with clinically suspected tinea pedis. [ncbi.nlm.nih.gov]

  CAUSES OF ERYTHRASMA As we known, it is caused by bacteria known as Corynebacterium minutissimum; hence it is often confused with other skin infections. [answers.yahoo.com]

  Since these lesions may be confused with cutaneous dermatophytosis, potassium hydroxide preparation is used to differentiate these two. Patients with recurrent episodes should be evaluated for diabetes. [symptoma.com]

  Erythrasma is sometimes confused with other skin infections that look similar, like: impetigo ringworm tinea infection fungal skin infections Washing your erythrasma scaly skin fold patches with antibacterial soap may help you conquer Corynebacterium. [healthblurbs.com]

• Irritability

  Natural Moisturizers Penetrate Deeply, Providing Multiple Benefits to Irritated Skin Jojoba Oil is one of the world's most nutrient-rich and long-lasting moisturizers. [aidanceproducts.com]

  Also allergic to Clindamycin so the topical lotion I was given only served to irritate things. There are only a couple months a year where I'm not fighting it. [drugs.com]

  A 12-year-old Hispanic girl, accompanied by her mother, presents with a 1-year history of a red irritated rash in both axillae (Figure 119-1). She has been seen by multiple physicians and many antifungal creams had been tried with no results. [accessmedicine.mhmedical.com]

  You can treat your erythrasma with over-the-counter products that help with itchiness and irritation. This might include hydrocortisone cream or miconazole cream. Light clothing. [webmd.com]

The workup will include a detailed history and identification of predisposing factors as well as a thorough physical exam of both feet and all body folds. 

Microscopy and culture are both methods to diagnose erythrasma. Scrapings are used for evaluation. Under ultraviolet radiation from Wood light examination, erythrasma will fluoresce a coral red color. This is a characteristic finding of these lesions since corynebacteria produce excess porphyrins that accumulate under the skin [6]. Furthermore, hyphae are not found in skin scrapings unlike in tinea. It must be noted that if the patient has bathed prior to this examination, the characteristic finding may not be present [7].

Specific culture media can be utilized as well. Gram staining is also useful. Erythrasma lesions appear as gram positive filamentous rods. Methylene blue stain can reveal both the curved rods of C minutissimum and fungal spores of pityriasis versicolor in cases where both organisms exist [8]. Of important note, patients with recurrence should raise suspicion for underlying diabetes and a workup may be appropriate.  

• Candida

  Candida: e.g., miconazole, clotrimazole, fluconazole Erythrasma: See “Treatment” below. [amboss.com]

  In some studies, up to 30 percent of patients with interdigital erythrasma have been found to have a coexisting dermatophyte or Candida albicans infection, usually noted in the third and fourth interspaces.2 Areas of the body that favor C. minutissimum [aafp.org]

  Concomitant fungal infections, predominately Candida, are seen in ~30% of patients. [unboundmedicine.com]

  This organism can be isolated from a cutaneous site along with a concurrent dermatophyte or Candida albicans infection. [ncbi.nlm.nih.gov]

There are various treatment options available. Eliminating the infection, along with preventing complications and recurrence are the therapeutic goals for these patients.

Antibiotic treatment

One regimen consists of erythromycin (drug of choice) or tetracycline: 250mg taken orally 4 times daily for a duration of 14 days (these are effective for extensive infection). Oral erythromycin is very effective and has cure rates up to 100%. This is more efficient than tetracycline in patients with erythrasma affecting axillae, groin, and interdigital lesions. Chloramphenicol can also be used, but this is associated with potentially severe side effects. To assess the usability of clarithromycin further studies need to be conducted. While C minutissimum is susceptible to numerous antibiotics such as erythromycin, tetracycline, penicillins, cephalosporins, and others, multidrug resistance has emerged [9] [10] [11] [12]. 

Medication particularly effective for interdigital infection and prophylaxis

• Topical erythromycin or clindamycin 
• Fusidic acid cream
• Whitfield ointment
• Antibacterial soap 

Phototherapy

Photodynamic therapy using red light (broadband, peak at 635 nm) is another method to treat erythrasma. In one study investigating the effects of phototherapy on erythrasma in 13 patients, 23% experienced complete clearance, and the remaining patients showed improvement [13]. 

A thorough clinical evaluation is pertinent to identify all organisms as there could be coexisting infections. The clinician should establish treatment to target all of these. Antifungals are used in concomitant yeast infections. It is important to keep the lesions dry since these bacteria flourish in moist environments. The area should be washed with antibacterial soap and topical aluminum chloride. As always when developing a treatment regimen, the clinician should be aware of drug interactions and side effects especially in pregnant women, women on oral contraceptives, and patients with contraindications. Many antibiotics have drug interactions and side effects. 

Erythrasma is typically benign. While the prognosis is very good, there is a possibility for recurrence as long as there are risk factors present. In immunocompromised patients, it may become widespread and invasive, but this is rare. C minutissimum can cause other diseases in these high-risk cases. 

Corynebacterium minutissimum, which is present in the normal skin flora, is the organism responsible for erythrasma. This skin infection can affect anyone but is especially present in individuals with diabetes mellitus, obesity or other underlying diseases [1] [2]. Those residing in warm damp climates are also at higher risk due to production of body moisture. Additional risk factors for erythrasma include hyperhidrosis, poor hygiene, older age, and sensitive skin. Immunocompromised hosts are also susceptible.

The incidence of erythrasma is approximately 4%. While its occurrence is reported globally, it has a higher prevalence in tropical and subtropical regions [3]. One study emerging from Turkey reports that erythrasma was the cause of interdigital foot lesions in 46.7% of patients with this presentation [4]. 

As for patient demographics, this infection is more common in black and dark skinned individuals but can affect anyone. Furthermore, both genders are affected equally (except for crural lesions which are more common in men). However, one particular study reports interdigital erythrasma was more commonly observed in women than men [5]. Finally, erythrasma is found in all ages, but incidence increases with age. Reports indicate that it was even diagnosed in a 1-year-old child. 

When in warm and humid climates, C minutissimum proliferates in the stratum corneum (which is the outermost layer of the epidermis). Hence, this layer becomes thick. Furthermore, the bacteria enter the cells and intercellular spaces subsequently causing break down of the keratin fibrils. This organism is also responsible for porphyrin synthesis, which results in the red fluorescence of scales that appear under examination of Wood light.

Prevention can be achieved through numerous recommendations. First of all, modification of risk factors should be addressed through improvement of glycemic control as well as weight loss. Additionally, patients should maintain good hygiene, use antibiotic soap, wear clean clothing, avoid humid and hot weather if possible, and keep the skin and especially skin folds dry. Prevention of recurrence is also achieved through these measures. The clinician may prescribe prophylactic treatment as well. 

Erythrasma, caused by Corynebacterium minutissimum, is an intertriginous infection usually found in individuals with predisposing factors such as diabetes, obesity, and darker skin. It is most prevalent in tropical or subtropical regions due to humidity and dampness. The culprit of this infection is a component of the normal skin flora. Favorable risk factors allow for this organism to multiply under the skin.

The clinical presentation of erythrasma can be confused with infections such as tinea versicolor and cutaneous dermatophytosis, which are due to other organisms. Therefore, a detailed exam of the body folds and feet is necessary.

This is typically a benign condition. Most patients will have an interdigital infection of the feet but remain asymptomatic. However, diabetics, immunocompromised individuals, and others may also have systemic involvement as the disease is targeting groin, axilla, and other moist folds.

Ultraviolet light is utilized to diagnose erythrasma. It reveals a characteristic coral red emission due to the porphyria produced by this organism. Treatment aims to eradicate the infection and prevent complications and recurrences. Therapy consists of antibiotics and/or antifungals as well, depending on the presence of coexisting organisms. Recognizing and modifying risk factors such as implementing better glycemic control and weight loss are also important in the treatment and prevention of this infection.

Erythrasma is an infection of the skin due to the bacterium Corynebacterium minutissimum. It usually appears as scaling and cracking in the skin between the 4th and 5th toes. The infection can also occur in areas of the body where there are skin folds such as the armpits, the skin below the breasts, or the abdomen. In women, it can appear on the vaginal/anal skin and in men it can be seen on the scrotum.

Erythrasma is common in diabetic and obese patients. Also, there are other factors increasing the risk of infection, for example as excessive sweating in addition to living in hot and humid environments such as tropical regions. 

This mild infection does not usually produce symptoms. Also, there are other skin infections that look very similar. Your doctor will examine your feet and skin carefully. Examination of the infected skin or scrapings from the skin with ultraviolet light will confirm the diagnosis.       

Treatment includes antibiotics such as erythromycin or tetracycline. There are other medications that can be applied to the infected skin. Good results are achieved with the available drugs. Also, it is recommended that some patients use preventative treatment. If there is yeast found on the infected skin, then your doctor will prescribe antifungal treatment in addition. 

Treatment and prevention of future episodes is important. Preventative measures are as follows: wash the skin with antibacterial soap and dry the skin well, practice good hygiene, avoid hot, humid weather if possible, and keep your body dry. Since the risk of infection is higher in patients with diabetes and obesity, improving glucose control and weight loss are also advised. 

1. Hodson S, Henslee T, Tachibana D, Harvey C. Interdigital erythrasma. Part I: A review of the literature. Journal of the American Podiatric Medical Association. 1988;78(11):551-558. doi:10.7547/87507315-78-11-551.
2. Sindhuphak W, MacDonald E, Smith EB. Erythrasma overlooked or misdiagnosed? International Journal of Dermatology. 1985; 24(2):2495- 96
3. Sarkany I, Taplin D, Blank H. Incidence and bacteriology of erythrasma. Arch Dermatol Archives of Dermatology. 1962;85(5):578. 
4. Inci, M, Serarslan, G, Ozer, B, et al. The prevalence of interdigital erythrasma in southern region of Turkey. Journal of the European Academy of Dermatology and Venereology. 2011;26(11):1372–1376.
5. Morales-Trujillo, M, Arenas, R, Arroyo, S. Interdigital Erythrasma: Clinical, Epidemiologic, and Microbiologic Findings. Actas Dermo-Sifiliográficas (English Edition). 2008;99(6):469–473.
6. Yasuma, A, Ochiai, T, Azuma, M, et al. Exogenous coproporphyrin III production by Corynebacterium aurimucosum and Microbacterium oxydans in erythrasma lesions. Journal of Medical Microbiology. 2011;60(7):1038–1042.
7. Mattox TF, Rutgers J, Yoshimori RN, Bhatia NN. Nonfluorescent erythrasma of the vulva. Obstetrics and Gynecology. 1993; 81(5 (Pt 2)):862-4.
8. Karakatsanis G, Vakirlis E, Kastoridou C, Devliotou-Panagiotidou D. Coexistence of pityriasis versicolor and erythrasma. Mycoses. 2004; 47(7):343-5.
9. Clayton YM, Connor BL. Comparison of clotrimazole cream, Whitfield's ointment and Nystatin ointment for the topical treatment of ringworm infections, pityriasis versicolor, erythrasma and candidiasis. British Journal of Dermatology. 1973; 89(3):297-303
10. Hamann K, Thorn P. Systemic or local treatment of erythrasma? A comparison between erythromycin tablets and Fucidin cream in general practice. Scandinavian Journal of Primary Health Care. 1991; 9(1):35-9.
11. Holdiness MR. Management of cutaneous erythrasma. Drugs. 2002; 62(8):1131-41.
12. Wharton JR, Wilson PL, Kincannon JM. Erythrasma treated with single-dose clarithromycin. Archives in Dermatology. 1998; 134(6):671-2.
13. Darras-Vercambre S, Carpentier O, Vincent P, Bonnevalle A, Thomas P. Photodynamic action of red light for treatment of erythrasma: preliminary results. Photodermatology, Photoimmunology & Photomed. 2006; 22(3):153-6.