Erythema Annulare Centrifugum - Causes, Symptoms, Diagnosis, and Treatment

What Is Erythema Annulare Centrifugum?

Erythema annulare centrifugum (EAC) is a rare skin rash. Small red bumps radiate from a central area of the rash. The bumps usually form a pattern that looks like a ring, but they can also spread out and take on different shapes. The center may become brighter and the rash may appear in more than one location.

EAC typically manifests on the legs or thighs. However, it can show up anywhere, including the arms, trunk, and face. The rash may appear for no apparent reason and disappear on its own, or it may indicate a deeper issue. It may appear simultaneously as an allergic reaction to food or drugs or after a spider or tick bite.

Additionally, EAC may indicate an infectious disease. There is an underlying illness or infection in about 13 percent of cases. It may occasionally indicate cancer. EAC rash typically begins in people 49 years old but can begin in infancy or at any age.

The EAC rash has a few other names, which include the following:

• Erythema perstans.

• Superficial or deep gyrate erythema.

• Palpable migrating erythema.

The Latin words for red rash (erythema), ring-like (annulare), and spreading from the center (centrifugum) are what give EAC its name.

What Causes Erythema Annulare Centrifugum?

The exact cause of the EAC rash is still not known. It may indicate an underlying disease or a hypersensitivity reaction. The triggers for the rash include the following:

• Allergy to some food.

• Arthropod bite (insect, spider, tick).

• Certain medications.

• Bacterial, viral, fungal, and parasitic forms of infectious diseases.

• Immune system or endocrine disorder, including Grave’s disease (overproduction of thyroid hormone), Hashimoto’s thyroiditis (thyroid gland not producing enough thyroid hormone), Sjögren's syndrome (characteristic dry eyes and dry mouth), and autoimmune progesterone dermatitis (recurrent skin eruptions during the luteal phase of the menstrual cycle).

• Hodgkin’s and non-hodgkin’s (cancer affecting the lymphatic system) lymphoma.

• Acute leukemia (abnormal, immature blood cells).

• Multiple myeloma (plasma cell cancer).

• Other cancers such as nasopharyngeal, breast, ovarian, or prostate cancer.

In 33 to 72 percent of cases, erythema annulare centrifugum is associated with underlying medical conditions and medications.

The most commonly associated conditions include the following:

• Internal malignancy.

• Cutaneous fungal infection (tinea pedis).

• Pregnancy.

• Adverse reaction to medications.

• Endocrine disorders (hormonal disorders).

• Hematological disorders (problems involving the blood and including the blood cells, bone marrow, lymph nodes, and spleen).

• Rheumatic disease (conditions affecting the muscles, bones, ligaments, tendons, and joints).

Blue cheese and tomatoes are two foods that can cause erythema annulare centrifugum in the body. The disease has also been linked to stress.

What Are the Symptoms of Erythema Annulare Centrifugum?

• Most of the time, erythema annulare centrifugum begins as a small pink papule that grows over a few weeks into annular plaques with a central clearing.

• The rash may itch or sting in some people, but most of the time, there are no symptoms.

• It is possible for the rash to develop a bull's eye-like appearance as it spreads outward. However, it can also take the form of an irregular shape or a uniform red circle. In addition, partially arciform angular lesions can coalesce into polycyclic (ringed), serpiginous (wavy), or gyrate (revolving) patterns. The annular or arciform lesions typically have a trailing (inner) scaly edge and an advancing outer erythematous edge.

• The size of a rash spot can range from less than a quarter of an inch to more than three inches. The thighs, buttocks, and upper arms are typically affected by erythema annulare centrifugum. However, the condition can affect any part of the body.

How Is Erythema Annulare Centrifugum Diagnosed?

The doctor will determine whether the rash is EAC through a visual and physical examination and a medical history. If the characteristic trailing scale is present, erythema annulare centrifugum can sometimes be diagnosed solely based on clinical features.

Skin Biopsy:

A skin biopsy that identifies the typical characteristics of superficial or deep erythema annulare centrifugum can be used to confirm the diagnosis: a "coat-sleeve" appearance caused by a dense perivascular lymphocytic infiltrate that involves either the superficial or deep vascular plexus. Parakeratosis (disturbance in the keratinization process), hyperkeratosis (thickening of the outer layer of the epidermis), and spongiosis (inflammation of intercellular edema) are examples of secondary epidermal changes.

Additional Tests:

The patient's history and the results of the examination should be used as guidelines when looking for an underlying cause. It is necessary to conduct a cancer screening based on age and symptoms. People who have fungal infections on their nails (tinea unguium), feet (tinea pedis), and crotch (tinea cruris) frequently develop EAC. If onychomycosis, tinea pedis, or tinea corporis is suspected, skin scrapings and toenail clippings should be sent to mycology.

The doctor may ask for other diagnostic tests to rule out other possibilities and determine if the rash results from an underlying disease. These tests may involve basic blood work and possibly a chest X-ray.

A review of a person's drugs can help determine if they may be having an allergic drug reaction. Drugs that may lead to EAC rash include

• Chloroquine.

• Amitriptyline.

• Cimetidine.

• Finasteride.

• Etizolam.

• Gold sodium thiomalate.

• Hydroxychloroquine.

• Hydrochlorothiazide.

• Penicillin.

• Rituximab.

• Piroxicam.

• Salicylates.

• Ustekinumab.

• Spironolactone.

How Is Erythema Annulare Centrifugum Treated?

An EAC rash typically goes away on its own if there is no underlying illness. This might take a few weeks or even months. After the previous rash has gone away, another one might appear. This process of getting better and returning can go on for months or years. The typical time frame is one year.

There is no tried-and-true cure. However, if the rash is itchy, the doctor may give an ointment or cream containing corticosteroid (cortisone) to help.

Whenever possible, the underlying cause of erythema annulare centrifugum must be identified and treated, such as a cutaneous fungal infection.

In some cases, alternative treatments that have been reported to be effective include the following:

1. Local Therapy: Topical medications that have reportedly been used to treat erythema annulare centrifugum include:

• Corticosteroids.

• Calcineurin inhibitors.

2. Systemic Therapy: Systemic medications reportedly being used for the treatment of the underlying cause of erythema annulare centrifugum include

• Azithromycin.

• Fluconazole.

• Metronidazole.

• Erythromycin.

In the case of widespread erythema annulare centrifugum, it has been reported that Etanercept makes the condition go away.

Conclusion

Erythema annulare centrifugum is a rare skin condition characterized by small red ring-like rash patterns that may or may not spread. They may be associated with an underlying medical condition. These rashes typically go away on their own, but if there is an underlying issue, it may need to be treated.