Nummular Eczema (Discoid Eczema) is a chronic condition of the skin which is characterized by the occurrence of coin shaped or disc shaped rashes on the surface of the skin [1]. These rashes prove to be quite irritating as they often tend to burn and itch.

These rashes are distinct and can be easily recognized thanks to the shape of spots. While sometimes it may be mistaken to be some form of skin injury such as that having been caused by a burn, an insect bite or an abrasion, the patches are almost always oval in shape, making it a recognizable form of eczema.

There may be an outbreak of one or several rashes of nummular eczema in an individual’s body depending on the severity of the condition. Typically, the rashes associated with eczema prove to last for duration of weeks and sometimes even stretches out to months.

Nummular eczema is not considered to be a serious or a life threatening condition. While anybody can be affected by nummular eczema the disease has been seen to be more commonly observed in elderly males between the ages of 55 to 60. If women tend to encounter the condition, they do so at a much younger age, primarily between the ages of 15 to 25. It is rare for children to be diagnosed with nummular eczema.

Nummular eczema is not a contagious disease and it cannot be transmitted from one person to another though direct contact.

Causes of Dyshidrotic Eczema

As with the other types of eczema, the exact cause behind nummular eczema is yet to be determined. While research is still being carried out in order to determine the reasons behind the condition, it is generally agreed upon that there is some sort of correlation between nummular eczema and allergic diseases such as hay fever or asthma. It may also be associated with other conditions of eczema such as atopic eczema.

While this still does not prove to say much about how the disease is developed in an individual, it is thought of that an allergic reaction is triggered off by an improper immune functioning of the body or certain genetic traits, which leave the individual prone to developing the condition when exposed to irritants such as pollen, dust, dirt, mites, chemicals and other environmental factors [2].

It is known that an individual may be sensitive to a number of factors and reports of nummular eczema have demonstrated that sensitivity to formaldehyde, nickel and mercury and certain antibiotics such as neomycin can lead to a development of the condition.

Studies have also shown that nummular dermatitis is developed more frequently in the following scenarios:

  • Individuals suffering xerosis or extremely dry skin may develop nummular eczema
  • Individual who have suffered an episode of statis eczema or atopic eczema may also develop nummular eczema
  • Individuals who have a poor circulation of blood in their bodies, especially in the lower extremities may prove to develop nummular eczema
  • Any injury caused to the skin surface such as those from abrasions or insect bites can lead to an individual developing the condition if harmful irritants are then contacted by the skin
  • Certain skin infections that have been caused by bacteria can also lead to the development of nummular eczema
  • Certain medications such as interferon and isoretinoin can prove to cause conditions of nummular eczema to be developed in some individuals

Signs and symptoms of Nummular Eczema

Typically, nummular eczema is an easily recognizable condition as the appearance of the rashes of the skin surface is in a distinct fashion. Conditions of nummular eczema are characterized by the appearance of blisters that are disc shaped or coin shaped. Initially, smaller blisters tend to appear in a group, which are often reddish and filled with fluid and then they enlarge and merge together into a discoid structure [3].

The blisters associated with nummular eczema are found to occur more commonly along the arms or along the feet of an individual and are often painful. If the blisters burst off, fluid oozes out of the lesion which makes the area completely dried out, crusty and scaly. The blisters often tend to itch and scratching is the primary cause of lesions in the skin.

Some of the other signs and symptoms that are associated with nummular eczema include the following:

  • Blisters are usually small in size and vary in diameter from one inch to four inches
  • Blisters are usually well defined in shape and appear to be reddish, pinkish or brownish in color
  • Itching and burning sensation on the blisters may range from moderate to severe
  • Symptoms of itching prove to cause significant discomfort at night, especially during sleep
  • Blisters become extremely dry, crusty and scaly if scratched

Sometimes, the signs and symptoms of nummular eczema may manifest themselves alongside a fever. When this is the case, it is quite often that the skin lesions and blisters are surrounded by inflammation, scales and appears to be reddish, raw and is extremely sensitive.

Very often, scratching the skin surface can also lead to an infection being developed. In such cases, a yellowish crust develops on the surface of the skin lesions being caused due to infection by the Staphylococcus aureus bacteria.

In between two coin shaped rashes, the skin surface may appear to be clear but it is often extremely dry and can be irritated quite easily.

The signs and symptoms of nummular eczema may get aggravated due to the following factors:

  • The skin being subject to extreme hot or cold weather conditions
  • Individuals taking up too much stress have a weakened immune function which greatly worsens symptoms
  • Irritants such as harsh chemicals found in soaps and detergents, certain metals such as chromium, cobalt or nickel and solvents like formaldehyde can worsen signs and symptoms
  • Deprivation of moisture leads to excessive dryness and can cause a great deal of discomfort
  • Presence of other types skin infections, allergies or even other types of eczema prove to be greatly detrimental to the condition
  • Any insect bites or injury to the skin surface greatly increases the risk of infection

Diagnosis of Nummular Eczema

Nummular eczema or discoid eczema is quite easy to diagnose thanks to the characteristic shape of the rashes that manifest themselves in the condition. Diagnosis of nummular eczema is usually confirmed after a careful visual examination of the rashes and after considering possible allergic reactions and a history of symptoms by a licensed medical professional.

It is in extremely rare cases that a blood test or a biopsy of the skin needs to be performed. If this is done, it is usually done in order to eliminate the possibilities of infections and diseases caused by other reasons such as infections caused by fungus or bacteria.

In some cases, patch testing on the skin may also be done in order to determine the possible factors an individual may be allergic to [4].

Prevention of Nummular Eczema

Nummular eczema is a chronic condition which has no definite cure. As such, it is best to prevent the occurrence of nummular eczema than having to deal with the irritation and frustration of the condition.

While it is still unclear as to what is the exact cause of nummular eczema, it is suspected to have a correlation with other forms of eczema and also allergies. As such, one should always avoid prolonged contact with harsh irritants such as those found in soaps, shampoos and detergents. The skin surface should be kept moist and lubricated and it is recommended to apply moisturizer to the skin at least twice a day. Taking long baths with hot water should be avoided as this leads to a dehydration of the skin.

Certain food groups may also prove to cause allergies and these need to be identified and avoided.  In general, food items with a high content of nickel such as oatmeal, canned foods and chocolates should be avoided.

Fabrics such as wool and synthetics may also prove to irritate the surface of the skin and these should ideally be replaced with light cotton garments.

Care must be taken whenever the skin meets with any injury or infection as such conditions increase the chances of developing nummular eczema. Individuals should never take up too much stress as it proves to weaken the immune system considerably.

Treatment of Nummular Eczema

The blisters and rashes that are associated with nummular eczema often prove to be very stubborn and difficult to get rid of. It is always advised to take proper treatment measures after consultation from a dermatologist in case you have been diagnosed with nummular eczema.

Self-measures that can be taken in order to facilitate the treatment procedures include:

  • Protecting the skin from any injuries such as cuts, insect bites and bruises
  • Hydrating the skin using moisturizers and lotions
  • Using wet cool compresses and medicated dressings
  • Taking adequate amount of rest and managing stress levels
  • Not indulging in activities which involve excessive sweating
  • Applying petroleum jelly on the skin surface

Some of the treatment procedures that a dermatologist may recommend in case of a moderate outbreak of nummular eczema include the following measures:

  • Prescription of antihistamines such as Benadryl or Claritin to help relieve the symptoms
  • Prescription soaks of potassium permanganate to help dry out the blisters and also to kill the bacteria
  • The use of prescription antibacterial sulphonamide drugs such as dapsone
  • Application of corticosteroid or steroid ointments on the blisters
  • The use of mineral or medicated oil atleast twice a day
  • Application of heavy creams like Eucerin or Lubriderm

In cases of severe outbreak of nummular eczema, the following treatment options may be employed:

  • Administration of steroid pills
  • Use of immune suppressant drugs such as Elidel and Protopic
  • Use of phototherapy or Ultra violet light therapy
  • Use of denorex or other coal tar preparations

While there are a number of medications and treatment procedures that can prove to be really helpful in the treatment of the signs and symptoms of nummular eczema, it must always be remembered that the condition is quite similar to that of an allergic attack and individuals who encounter the condition are more prone to allergic attacks than others. Some of the medications and drugs that may be used in the treatment of nummular eczema can prove to cause allergies in an individual, leading to the development of a condition that is known as contact eczema. As such, it is always important to determine the complete history of the signs and symptoms of an individual, as also try to ascertain the possible allergens and irritants before moving on to commence with treatment plans and methods.

Is Nummular Eczema contagious?

Nummular eczema is not a contagious disease and it cannot be spread to a healthy individual via contact from a sufferer.

Recurrence and future complications

While nummular eczema may not be a serious or a life threatening condition in any way, it does prove to be a painful and irritating condition and is typically a chronic one which lasts throughout the lifetime of an individual.

Very often, the blisters that are associated with nummular eczema do not heal completely and a new outburst of rashes appears [5]. While the normal duration of the course of these blisters may range in several weeks, scratching the skin surface may prolong the condition and extend it into several months.

Scratching the skin surface can also lead to the development of secondary infections from certain viruses, fungi and bacteria. Also, scratching breaks open the blisters which leave behind ugly scars even long after healing.

Nummular eczema is also associated with complications such as the development of some seasonal allergies including hay fever and asthma or the development of other forms of eczema such as statis eczema or atopic eczema. While the correlation between these conditions is yet to be understood fully, there is definitely no doubt that there proves to be some common link or triggering factor for all of these conditions.



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[2] Molecular phylogenetic analysis of Orientia tsutsugamushi based on the groES and groEL genes, Tabara K, Yamamoto N, Fujita H; PMC3822374- 2013 Oct 9-DOI :10.1089/vbz.2012.1155,

[3] Loss of activating EGFR mutant gene contributes to acquired resistance to EGFR tyrosine kinase inhibitors in lung cancer cells, Kanda R, Sonoda K, Kubo T, Murakami Y;PMC3398867- 2012 Jul 17- DOI: 10.1371/journal.pone.0041017,

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[5] Divergent ancestral lineages of newfound hantaviruses harbored by phylogenetically related crocidurine shrew species in Korea, Arai S, Gu SH, Baek LJ; 424(2):99-105-2012 Mar 15- DOI: 10.1016/j.virol.2011.11.013,