Erythrasma

What is Erythrasma?

Erythrasma is a common skin condition caused by bacteria. It was first recognized in 1859 by a scientist named Burchardt who wrongly believed it to be a fungal infection. Then, in 1862, Burchardt’s mentor, Von Barensprung assigned the name ‘erythrasma’ and identified the bacteria as Microsporum minutissimum. These days, we know the real culprit to be Corynebacterium minutissimum, a specific type of bacteria.

This bacterium, which is gram-positive (meaning it can be identified using a particular staining technique), doesn’t produce spores and contains an enzyme called catalase. Erythrasma mostly impacts certain areas of the body where skin rubs together and can cause itching, flaky skin, and redness. However, it often shows no symptoms at all.

What Causes Erythrasma?

In 1961, researchers named Sarkay and his team closely examined parts of a skin condition called erythrasma. They found a type of bacteria, C. minutissimum, which they observed as tiny little rods under a microscope. It turns out this bacteria, which is usually harmless and lives on our skin, can cause severe skin and health issues in people with weakened immune systems. In these cases, it could lead to skin tunnels (cutaneous fistulas), sores and bumps (granulomatous lesions), and pockets of pus beneath the skin (subcutaneous abscesses).

The reason why this bacteria gets attention is because of its potential to cause severe problems for people with compromised immune systems. That’s why the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, has taken a deep look at the genetic material of this bacteria, to better understand it.

There are also certain conditions and factors that might increase the chances of getting erythrasma. These include living in a humid environment, sweating a lot, having diabetes, not maintaining good hygiene, being older, having other skin disorders, and being overweight.

Risk Factors and Frequency for Erythrasma

Erythrasma, an infection, occurs mainly in healthy adults and is less frequent in children. It’s found more in hot and humid climates and also more likely to occur in people living in group settings. These include college students staying in dorms, soldiers in barracks, and older adults in nursing homes. As people get older, the chances of getting erythrasma may increase. It is seen all over the world and could happen more in males. However, it appears that erythrasma is most common in African Americans.

Signs and Symptoms of Erythrasma

Erythrasma is a skin condition that typically occurs between the toes or in the folds around the groin, but can also be found in the underarm area. When a person has Erythrasma, they might notice a dark red and moist discoloration of the skin in these areas, which can sometimes be itchy. The affected skin may also appear to be peeling slightly and be well defined from healthy skin, often taking on a wrinkled look.

• The condition is mostly found between the toes or in the folds of the groin
• The affected skin is typically dark red, moist, and may be slightly itchy
• There can also be peeling or scaling of the skin
• The affected areas are well defined and may appear wrinkled

There are several types of Erythrasma, each with slightly different characteristics:

• Interdigital: This is a bacterial infection typically occurring between the toes, especially the fourth and fifth toes. It can cause the skin in these areas to soften and peel, and may cause itching. This type of Erythrasma can sometimes occur alongside fungus or yeast infections and requires laboratory testing to confirm.
• Intertriginous: This type can cause patches or raised areas of skin in the folds of the body, such as under the arms or around the groin. The affected skin may have a fine scale and resemble the texture of “cigarette paper.” It can be itchy, but not always.
• Disciform: This rare form of Erythrasma can occur anywhere on the body. It’s more commonly seen in black women who live in tropical climates and is characterized by well-defined, scaly patches on the chest, back, and upper limbs. When examined under a specific type of light (Wood’s lamp), the plaques glow a coral-red color.

Testing for Erythrasma

A Wood’s lamp, which is a special kind of light, can be used to help diagnose erythrasma, a skin condition. When exposed to this light, the erythrasma bacteria produce a color caused by something called coproporphyrin III made by the bacteria.

If no Wood’s lamp is available, the doctor might begin treatment based on the physical examination of your skin alone.

In some cases, a skin biopsy (taking a small sample of the skin to examine) may be taken to identify erythrasma. The sample may show rod-shaped organisms, which are the bacteria that cause the condition. However, these bacteria can be hard to see, requiring special staining methods with substances like Giemsa or Periodic Acid-Schiff. Because of this, and since skin biopsy is a more invasive procedure, it’s typically not the first choice when trying to diagnose erythrasma.

Treatment Options for Erythrasma

Erythrasma is a skin condition that, while it can be treated with both topical and oral medication, has a tendency to return. Some typical topical treatments include creams with fusidic acid, clindamycin, or erythromycin. Fusidic acid, an antibiotic not available in the United States, works by preventing certain bacteria from producing proteins necessary for their survival.

In a reliable study conducted at the University Hospital in Izmir, Turkey, 151 adults were split into five groups to compare the effectiveness of these different treatments. Each group was given a different treatment, including oral clarithromycin, oral erythromycin, a placebo, topical fusidic acid cream, or a placebo cream.

Fusidic acid cream was found to be better than the oral clarithromycin and erythromycin at decreasing the intensity of the glow seen under Wood’s lamp, a special light used to identify certain skin conditions. This was possibly due to fusidic acid’s ability to remove a specific substance, coproporphyrin III, from the upperlayer of the skin. Fusidic acid was also found to completely heal 96% of patients, while clarithromycin healed 66% of patients and erythromycin healed 53%.

In cases of more wide-spread erythrasma, oral treatment is required. This can include a one-time dose of clarithromycin or a two-week treatment of erythromycin.

Clarithromycin, another antibiotic, has a few benefits over erythromycin. One main advantage is that it can be given as a single dose. It works by interfering with bacteria’s protein production by binding to part of the bacteria’s protein factory. Clarithromycin is more easily absorbed by the body than erythromycin because of a small structural difference. It might be more effective in treating erythrasma found in the groin area, however, not many studies have made the comparison between both.

Both oral treatment options come with some side effects, which can include nausea, stomach pain, hearing loss, a metallic taste in the mouth, irregular heart rhythem, yellowing of the skin and eyes, and a severe skin reaction.

What else can Erythrasma be?

When a doctor tries to diagnose erythrasma, they also need to consider other conditions that could be causing the symptoms. These include:

• Seborrheic dermatitis
• Inverse psoriasis
• Candidiasis
• Dermatophytosis
• Tinea versicolor
• Parapsoriasis
• Pityriasis Rotunda

Seborrheic dermatitis usually causes greasy, reddish patches on the scalp or around the nose. Inverse psoriasis tends to make the skin look shiny. Erythrasma can be set apart from these two conditions with something called Wood’s lamp exam, which reveals a coral-red glow.

Sometimes, a test using potassium hydroxide solution (KOH prep) might be necessary to tell the difference between erythrasma and dermatophytosis of the toe webs. Erythrasma in the groin can be distinguished from another condition called tinea cruris because tinea cruris has a certain boundary look that erythrasma doesn’t have.

What to expect with Erythrasma

The results for most patients dealing with erythrasma, a type of skin infection, are generally very favorable. However, the condition can reappear if the elements causing it are not eliminated. For healthy people, erythrasma doesn’t lead to any lingering health issues. Yet, the infection can spread much faster in individuals with a weakened immune system.

Possible Complications When Diagnosed with Erythrasma

People with weakened immune systems are more likely to experience complications, like:

• Endocarditis: an infection of the inner lining of the heart
• Abscess formation: the development of pus-filled pockets in the body
• Intravascular catheter infection: an infection related to a catheter, a tube that can be inserted in the body to deliver or drain fluids
• Cellulitis: a skin infection
• Pyelonephritis: a type of kidney infection