What is Nummular Eczema (Discoid Dermatitis)?
Nummular eczema, also termed as discoid eczema and nummular dermatitis, is a form of eczema that is characterized by an unusual and unique, coin-shaped lesion. The appearance of this skin condition makes it different from the other types of eczema and it can be one of the most difficult skin ailments to be treated. Nummular dermatitis derive its name from a Latin word “nummus” that means “coin”. The prevalence of this rare condition is estimated to be approximately 2 per 1000 persons in the United States. Discoid eczema is most common amongst the adults, in comparison to the children.
Nummular Eczema Causes
The cause of Nummular eczema is still unknown. As per the researchers and experts, the hereditary and environmental factors may affect the skin of an individual. However, people with atopic dermatitis, allergies or asthma may develop discoid eczema. Many people with Discoid eczema tend to have a sensitive skin that easily gets irritated.
What are the Nummular Eczema Triggers?
- Dry skin
- Temperature changes (especially winter season is unfavorable)
- Cold and dry air
- Insect bite or scratch
- Environmental irritants, such as soaps, metals, and formaldehyde
Similar to atopic dermatitis, bacteria can infect nummular dermatitis and cause wet, open sores.
A Research on Discoid Eczema and Contact Allergy:
“Nummular eczema and contact allergy: a retrospective study”
What are the Symptoms of Nummular Eczema?
The most noticeable and distinguishing symptom of nummular eczema is a single patch or multiple patches of coin-shaped plaques or lesions on the body. These lesions most commonly affect the arms and legs (upper and lower limbs), but they might spread to the torso, dorsum of the hands.
They may appear brown, pink, or red in color. Some lesions are itchy and may cause burning sensation, while, others may ooze and eventually crust over. The skin surrounding these lesions may become red, scaly, or inflamed.
It may take several months to treat these patches. If you suspect of having discoid eczema, it is highly recommended to consult a dermatologist.
Ensure to treat the condition at the right time otherwise it may increase the chances of developing secondary skin infection. Once the lesions gets infected, a yellowish crust will be formed.
Who is at Risk for Nummular Eczema (Discoid Eczema)?
The skin condition may affect children and adults both, but is more common amongst adults. The occurrence of discoid eczema is more common amongst adult males in comparison to women. Additionally, men over the age of 50 are at an increased risk of developing this types of eczema.
The following conditions may increase your risk of developing discoid eczema:
- living in a cold, dry climate
- having dry skin
- having poor blood flow or swelling in the legs
- having another type of eczema
- having a skin injury, such as an insect bite or abrasion
- having a bacterial infection that affects the skin
How is Nummular Eczema diagnosed?
Nummular eczema is often confused with a ringworm in adults and tinea corporis in case of children. Hence, medical intervention is necessary. Your doctor may visually inspect the skin to diagnose the symptoms of nummular eczema or may inquire about your medical history (if required).
The dermatologist can recommend you to perform a skin biopsy in order to rule out the chances of infection. Skin lesion biopsy includes removal of a small portion of the skin tissue from the affected area and testing it for the presence of bacterial colonization.
To rule out the possibilities of an allergic reaction or contact allergy, they may also perform an allergy test or patch testing. This may include skin tests or blood tests to help determine the specific allergy.
How is Nummular Eczema treated?
Similar to other forms of eczema, there is no cure for nummular eczema. However, you can treat and manage your condition by making certain changes in the lifestyle, by adopting the necessary measures and avoiding triggers.
The below mentioned measures and remedies can help manage discoid eczema:
- Safeguard the skin from injury: Abrasions or wounds are considered to develop the symptoms of discoid eczema. In case of injury, ensure to prevent the wounded area to come in contact with a susceptible allergen or excessive water. If required you can cover the areas, like hands with gloves.
- Apply Emollients: Emollients majorly include skin-hydrating products like bath oils, soap substitutes and moisturizing creams. The application of these products directly on the skin provides relief against itching, scaling and dryness. You may also use emollients on the unaffected skin to reduce dryness.
- Topical steroids: Application of topical steroids is a common treatment for managing the symptoms of discoid eczema. These anti-inflammatory creams or ointments are available on medical prescription by your dermatologist to help reduce irritation and prevent eczema flare-ups. Depending upon the potency of the product, the stronger ones are recommended to be applied once or twice in a day on the affected area for 2–4 weeks. They may be repeated from time to time (if required). The mild ones like hydrocortisone can be used on a daily basis, if needed.
- Antibiotics: The dermatologist may prescribe antibiotics to tackle the blistered, sticky or crusted skin. In a few cases, the eczema may clear up completely with a irregular intake of oral antibiotics, but may reoccur as soon as these antibiotics are discontinued.
Related: What causes Seborrheic Dermatitis?
More severe cases of Discoid Eczema may respond to:
- Oral antihistamines
Oral antihistamine pills are found beneficial in reducing the itching, and they are particularly effective during the night-time. However, the treatment method doesn’t help clear the dermatitis. Also, it has been analyzed that the first-generation antihistamines are more useful in comparison to the non-sedating antihistamines for discoid eczema.
- Ultraviolet radiation (UV) treatment
The UV radiation treatment repeatedly carried out for 6–12 weeks can help reduce the severity of nummular eczema.
Related: Top 10 Contact Allergens
Can Discoid Dermatitis be treated completely?
Nummular dermatitis is more often a chronic condition. It is possible that some of the lesions may be removed completely while the others may reoccur. It may take long time to heal the lesions on a few areas and may also leave behind dark or light spots.
Despite the complications, discoid eczema can usually be managed with a proper medical advice and by avoiding the factors or allergens that may trigger the symptoms of Discoid eczema.