What Is Erythema Annulare Centrifugum?
If you have noticed strange red bumps forming ring-like patterns on your skin, you might be dealing with erythema annulare centrifugum (EAC). This uncommon rash typically starts as small red bumps that spread outward from a central spot, creating rings or other shapes. You'll usually spot it on your legs or thighs, though it can pop up anywhere on your body.
Sometimes it's harmless and disappears on its own, but it could signal an allergic reaction, infection, or, rarely, something more serious. While it's most common around age 49, anyone can develop it.
What Causes Erythema Annulare Centrifugum?
Doctors are still not entirely sure what causes the EAC rash. It might be your body's way of telling you that something is not quite right; either there is an underlying health issue, or you are having a hypersensitivity reaction.
The triggering factors are as follows:
- You might be allergic to certain foods.
- A bug bite could be the culprit (insects, spiders, or ticks).
- Some medications you are taking.
- Various infections, whether they are bacterial, viral, fungal, or parasitic.
- Pregnancy.
- Hormone imbalances.
- Believe it or not, something as simple as eating blue cheese or tomatoes can trigger this rash in some people.
- If you're going through a stressful time, that might bring it on, too.
- Your immune system or hormones might be acting up. This includes conditions like Graves' disease (when your thyroid goes into overdrive), Hashimoto's thyroiditis (when your thyroid's too sluggish), Sjögren's syndrome (which leaves you with dry eyes and mouth), and autoimmune progesterone dermatitis (those annoying skin flare-ups during certain times of your menstrual cycle).
- Cancers like lymphomas (lymphatic system cancer), acute leukemia (when your blood cells don't develop properly), and multiple myeloma (blood cancer). Other cancers, such as those affecting your nasopharynx, breast, ovaries, or prostate.
- Blood-related problems (affecting your blood cells, bone marrow, lymph nodes, or spleen).
- Rheumatic conditions (these mess with your muscles, bones, ligaments, tendons, and joints).
What Are the Symptoms of Erythema Annulare Centrifugum?
You might first notice small, pink or red bumps that feel itchy or tender, often appearing on your thighs, legs, or torso. These rashes spread outward from where they began, growing by about 2 to 5 millimeters each day. As they get bigger, the middle part actually clears up. This leaves you with these distinctive ring-shaped or wavy patterns.
The rash itself can be raised and might feel itchy or tender, though sometimes you won't feel anything at all. You will most commonly find these patches on your thighs and buttocks, but they can also pop up on your trunk, face, and arms. They usually don't affect your palms or soles.
What makes EAC particularly frustrating is that it tends to stick around. You might be dealing with it for months or even years, with lesions coming and going. Some people notice that after the rash fades, it leaves behind a temporary dull red or brownish discoloration on the skin. While it's not dangerous, the chronic nature of EAC means you will likely need patience as you work with your doctor to manage it.
How Is Erythema Annulare Centrifugum Diagnosed?
Your doctor will determine whether you have EAC by carefully examining your rash, asking about your medical history, and considering other factors. Sometimes, if they spot that telltale trailing scale pattern, they can diagnose erythema annulare centrifugum just by looking at it.
Skin Biopsy:
If your doctor wants to be absolutely sure, they might take a small skin sample. This skin biopsy can confirm EAC by showing specific features: you will see a "coat-sleeve" pattern, which occurs when lymphocytes (a type of white blood cell) crowd around your blood vessels. The biopsy might also reveal changes in your skin's outer layer, such as unusual thickening or inflammation between cells.
Additional Tests:
Your doctor will use your history and exam results to guide them in finding what might be causing your rash. They'll recommend cancer screening that's appropriate for your age and symptoms. If you have fungal infections on your nails, feet, or groin area, you're more likely to develop EAC. So if your doctor suspects any fungal infections, they'll send nail clippings or skin scrapings to the lab for testing.
Your doctor might order additional tests to rule out other conditions and determine whether an underlying disease is causing your rash. You'll probably need some basic blood work, and maybe a chest X-ray, too.
They'll also review any medications you're taking since certain drugs can trigger an allergic reaction that shows up as EAC. The medications that might cause this rash include:
- Chloroquine.
- Amitriptyline.
- Cimetidine.
- Finasteride.
- Etizolam.
- Gold sodium thiomalate.
- Hydroxychloroquine.
- Hydrochlorothiazide.
- Penicillin.
- Rituximab.
- Piroxicam.
- Salicylates.
- Ustekinumab.
- Spironolactone.
How Is Erythema Annulare Centrifugum Treated?
If you have an EAC rash and no underlying illness is causing it, it will usually clear up on its own. You might need to be patient, though, as this can take anywhere from a few weeks to several months. Once your rash disappears, another one might pop up. This frustrating cycle of clearing up and coming back can continue for months or even years, typically lasting about a year.
The first point is figuring out what is causing your rash. If you have something like a fungal skin infection triggering it, treating that underlying issue is your best bet.
Unfortunately, there is no magic cure that works for everyone. If you are looking for treatment options, below are the treatment options.
But if you are dealing with itchy skin, your doctor can prescribe a corticosteroid (Cortisone) cream or ointment and Calcineurin inhibitors, to give you some relief. These medicines can be applied directly to your skin.
Your doctor can give you medications you take by mouth. These are usually prescribed when there is an underlying condition to treat:
- Azithromycin.
- Fluconazole.
- Metronidazole.
- Erythromycin.
For those dealing with widespread rashes covering large areas of skin, some people have had success with the medication Etanercept, which has been reported to clear the condition completely.
Conclusion
Erythema annulare centrifugum is a small, red ring that appears on your skin. It's rare, but basically, these ring-shaped rashes can either stay or spread outward. Sometimes they're just a random skin thing, but other times your body might be trying to tell you something else is going on underneath.
These rashes usually clear up on their own without causing any damage. But if there is an underlying health issue causing them, you'll want to get that sorted out with the skin care specialist. Your doctor will prescribe topical or systemic steroids to treat this infection.
Key Takeaways
- EAC is a skin condition characterized by red, ring-shaped patches that grow outward while the center clears.
- It's a hypersensitivity reaction in your body, not a primary skin problem.
- You might develop this reaction from various triggers like fungal infections or certain medications (including antidepressants or heart drugs), or sometimes it's linked to underlying cancers like lymphoma.
- It is usually harmless and resolves once the underlying cause is treated with topical steroids for comfort.
