Nummular eczema, also called nummular dermatitis, is an inflammatory skin condition characterized by round, well-defined lesions that resemble coins. Although not as well known as atopic or contact dermatitis, this specific type of eczema can cause significant physical and emotional discomfort, especially when mistaken for contagious infections. In this text, we’ll explore what nummular eczema is, its possible causes, symptoms, treatments, and debunk common myths related to the condition.
What is nummular eczema?
The word “nummular” comes from the Latin numulus, meaning “coin.” The name refers to the characteristic shape of the lesions: round plaques, usually with well-defined, reddish edges that itch and may flake or even form crusts. These lesions most often appear on the arms, legs, back, and hands but can show up elsewhere on the body as well.
The condition may present acutely or chronically, with periods of improvement and worsening over time. In some cases, the plaques may become infected, increasing severity and requiring immediate medical attention.
Causes and triggers
The exact cause of nummular eczema is still not fully understood, but several factors appear to be involved:
Dry skin: the loss of the skin’s natural protective barrier makes inflammation and lesion development easier.
Contact with irritants: cleaning products, harsh soaps, synthetic fabrics, and other chemicals may worsen the condition.
Previous infections: in some people, prior skin infections or lesions can trigger or worsen flare-ups.
Emotional stress: as with other types of eczema, stress can act as a trigger.
Environmental factors: dry, cold weather or low humidity also contribute.
Unlike atopic dermatitis, which usually has a genetic component and often begins in childhood, nummular eczema can appear at any stage of life, especially in middle-aged and older adults.
Most common symptoms
The main symptoms include:
Round, reddish plaques with intense itching
Peeling and crusts on the affected areas
Wet lesions or the presence of small blisters
Burning or stinging sensation
Worsening of symptoms during winter or in dry environments
It is common for the lesions to be symmetrical and appear repeatedly in the same locations, especially during recurrent flare-ups.
Diagnosis and differentiation
Diagnosis of nummular eczema is clinical, made by a dermatologist based on the appearance of the lesions and the patient’s history. In some cases, tests may be required to rule out fungal or bacterial infections, psoriasis, or other skin conditions that may look similar.
Self-diagnosis should be avoided, as improper medication use can worsen the condition or hide infections that require specific treatment.
Treatment of nummular eczema
Treatment for nummular eczema aims to relieve symptoms and restore the skin barrier. The main approaches include:
Intense hydration
Keeping the skin well moisturized is essential. Thick, fragrance-free emollient creams should be applied several times a day, especially after bathing.
Topical corticosteroids
Corticosteroid ointments and creams help reduce inflammation and itching. They should be used under medical supervision and for a limited time to avoid side effects.
Antibiotics
If the lesions become secondarily infected, topical or oral antibiotics may be necessary.
Phototherapy
In more severe or recurrent cases, controlled exposure to ultraviolet light (UVB) may be recommended by a dermatologist.
Oral medications
In persistent cases, the doctor may prescribe antihistamines to control itching, or mild immunosuppressants depending on severity.
Attention: all medications should only be used with medical prescription. Self-medication may worsen the condition and cause unwanted side effects.
Myths and truths about nummular eczema
As with other dermatological conditions, nummular eczema is surrounded by misinformation. Here are some common myths:
“It’s contagious” – Myth! Nummular eczema is not caused by viruses, fungi, or transmissible bacteria. It is not passed from person to person.
“It’s caused by poor hygiene” – Myth! The condition is related to factors like skin dryness and sensitivity to irritants, not to cleanliness.
“It’s just dry skin and cold weather” – True! These factors contribute, but are not the only causes of the condition.
“It has a cure” – Partially true. Nummular eczema can be managed with proper treatment, but it tends to be chronic and recurrent.
Daily care and prevention
Maintaining a daily care routine is essential to prevent flare-ups:
Avoid very hot or prolonged showers
Use gentle, moisturizing soaps
Apply strong moisturizers daily
Wear cotton clothing and avoid irritating fabrics
Reduce stress when possible
Protect skin from sudden temperature changes
Living with nummular eczema
Although it has no definitive cure, it is possible to live well with nummular eczema. Identifying personal triggers, following treatment properly, and keeping the skin hydrated are key to controlling the condition. Regular dermatological check-ups help monitor progress and adjust treatment as needed.
