Nummular Eczema: What You Should Know

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Rashes can be the worst, especially if they are itchy. A condition called eczema, also known as atopic dermatitis, is an itchy rash that usually precedes other symptoms including allergic rhinitis, food allergies, and asthma. There are different types of eczema, including one called nummular eczema.

What Is Nummular Eczema?

Nummular eczema is a type of eczema rash that is coin-shaped. The word "nummular” means coin in Latin.

When nummular eczema happens, there usually a disruption in the skin barrier which allows allergens through the skin. This may cause the rash. Atopic dermatitis is usually related to being allergic to various things while nummular eczema is generally associated with contact dermatitis.

Symptoms 

Nummular eczema appears as round, disc-like lesions and can appear anywhere on the body. It is most likely found on the arms and legs.

The lesions can be very itchy, while some people say the lesions are only itchy when they are just developing. There may be crusting over the lesion and the rash can have liquid drainage. There may also be redness around the lesion.

Nummular eczema can cause pain and can also be the cause of emotional stress because of its appearance. But many patients are able to get help from their physician.

Causes

Different conditions may cause or aggravate nummular eczema. These include:

  • Dry skin
  • Contact dermatitis
  • Weather
  • Emotional stress (stress may make you feel itchier)
  • Oral medications including interferon (usually used to treat hepatitis) or isotretinoin (a popular acne medication)
  • Topical medications including topical antibiotic creams like Neosporin
  • Previous skin damage including a burn or other wound, open skin from scratching, or insect bite

Nummular eczema does not generally affect children. It is more likely to affect men who are between the ages of 55 and 65. Women generally experience their initial nummular eczema episode between the ages of 13 and 25.

Diagnosis

Accurate diagnosis of nummular eczema can be difficult as the rash may appear different on different skin types. So your doctor will likely ask you a lot of questions.

Also, your doctor may need to rule out other skin diseases that resemble nummular eczema. This is done with a skin biopsy. The biopsy sounds scary, but the test is performed with local anesthesia and most patients say it is not too bad. The biopsy allows a pathologist to examine the skin under a microscope to help determine the cause of the rash.

A patch test to look for contact dermatitis may also be beneficial for patients with nummular eczema. The patch test helps in diagnosing if any personal products or other agents that you are exposed to could be worsening your rash. The most common culprit is nickel, but fragrances, rubber products, and others can be the cause as well.

The patch test is a three-day test that is placed on your back. It is important not to get your back wet with water or sweat as it can interfere with the patches and then provide inaccurate results. On the last day of your test, the physician will read your patch test and give you a list of what you are allergic to. It is exciting to have a positive test because it means you can actually avoid products that are worsening your eczema.

The most common diagnosis nummular eczema gets confused with is a fungal skin infection. A fungal infection can also be itchy which adds to the confusion between the two diagnoses. The treatment for the different rashes differs greatly, so it is important to see a physician for the correct diagnosis.

Treatment

The best treatment for nummular eczema is topical steroids. Generally, a strong topical steroid (rather than a milder form) is needed to help resolve the rash.

Topical steroids have important side effects including:

  • Hyper or hypopigmentation of skin which means it can change the color of your skin
  • Telangiectasias (enlarged blood vessels, usually capillaries)
  • Skin atrophy (skin thinning)
  • Easy bruising
  • Increased risk of skin infection

Typically, you will only experience these side effects if you use topical steroids for a prolonged period of time or on an injured skin surface.

Your physician may ask you to be extra cautious in areas like the face, neck, underarms (axilla) and groin area, as skin is thinner in these areas and is more likely to suffer from the adverse effects listed above. Make sure you and your doctor are monitoring your steroid use.

Other topical agents including Tacrolimus or Pimecrolimus work on a different pathway and can also help with nummular eczema. These agents are not steroids, so they carry much less adverse effects but may not be as helpful as the first line therapy which is topical steroids. It is important to note that these topical creams can cause burning after application.

Eucrisa is a new topical medication that is also not a steroid and may be helpful in those that are unable to use topical steroids.

Antihistamines are another great class of medications to help with nummular eczema. Antihistamines may include Cetirizine, Fexofenadine, Levocetirizine, and Loratadine. Some of these medications can be taken more than once a day to relieve the annoying itch.

Nummular eczema can look a little worse if there is concurrent infection overlying the rash. Usually, the most common organism found in culture is Staphylococcus aureus. If found, it will require additional treatment, most likely with an oral antibiotic. Let your doctor know if you develop a fever or chills as these symptoms may indicate an infection.

Oral steroids may also be helpful if the rash is worse than usual. Steroids are not usually the best treatment option because it can worsen dermatitis after the steroid taper.

Prognosis

Nummular eczema is considered a chronic condition that cycles between flares and quiescence. It is important to keep skin hydrated and avoid exacerbating factors which may include allergens found on your patch test, topical medications as listed previously and management of your stress.

View Article Sources
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