Summary about Disease
Nummular dermatitis (also known as nummular eczema or discoid eczema) is a chronic inflammatory skin condition characterized by coin-shaped (nummular) itchy, inflamed patches on the skin. The patches can be dry, scaly, or weepy, and they often appear on the arms, legs, and torso. It is not contagious.
Symptoms
Coin-shaped (round or oval) lesions on the skin.
Intense itching (pruritus) that can be worse at night.
Dry, scaly, or crusty patches.
Patches that may be red, pink, or brown.
Small blisters or papules within the patches.
Weeping or oozing from the patches (especially if scratched).
Cracked skin.
Possible burning sensation.
Causes
The exact cause is unknown, but it is likely a combination of factors. These may include:
Dry skin
Sensitive skin
Genetics (family history of eczema or allergies)
Irritants (soaps, detergents, fragrances, chemicals)
Allergens (pollen, pet dander, certain metals like nickel)
Insect bites
Stress
Changes in temperature or humidity
Bacterial infection (such as Staphylococcus aureus)
Poor blood flow to the lower legs
Medicine Used
Topical Corticosteroids: These are the mainstay of treatment to reduce inflammation and itching. Examples include hydrocortisone, triamcinolone, and betamethasone. The strength of the corticosteroid depends on the severity of the condition.
Emollients (Moisturizers): Frequent use of thick, fragrance-free moisturizers is crucial to hydrate the skin and repair the skin barrier.
Topical Calcineurin Inhibitors: These medications, such as tacrolimus (Protopic) and pimecrolimus (Elidel), are non-steroidal and can be used for long-term management, especially on sensitive areas like the face.
Antihistamines: Oral antihistamines can help relieve itching, especially at night.
Topical or Oral Antibiotics: Used if there is a secondary bacterial infection.
Coal Tar Preparations: Can help reduce itching and inflammation.
Phototherapy (Light Therapy): Exposure to ultraviolet (UV) light can help reduce inflammation.
Systemic Corticosteroids (Oral or Injected): Used in severe cases, but usually for short periods due to potential side effects.
Dupilumab (Dupixent): An injectable biologic medication that can be used for severe eczema that has not responded to other treatments.
Is Communicable
No, nummular dermatitis is not communicable or contagious. It cannot be spread from person to person.
Precautions
Moisturize Regularly: Apply thick, fragrance-free moisturizers several times a day, especially after bathing.
Avoid Irritants: Use mild, fragrance-free soaps and detergents. Avoid harsh chemicals and solvents.
Bathe in Lukewarm Water: Hot water can dry out the skin. Keep baths short (5-10 minutes).
Pat Skin Dry: After bathing, gently pat the skin dry instead of rubbing.
Avoid Scratching: Scratching can worsen the condition and lead to infection. Keep nails short and consider wearing gloves at night.
Identify and Avoid Allergens: If possible, identify and avoid any known allergens that trigger outbreaks.
Wear Loose-Fitting Clothing: Avoid tight-fitting clothing that can irritate the skin. Choose soft, breathable fabrics like cotton.
Manage Stress: Stress can trigger outbreaks. Practice relaxation techniques such as yoga or meditation.
Humidify Your Home: Use a humidifier to keep the air moist, especially during dry seasons.
How long does an outbreak last?
The duration of a nummular dermatitis outbreak varies. With treatment, a flare-up may resolve in several weeks to a few months. Without treatment, or if triggers are not addressed, outbreaks can persist for longer periods. Chronic or recurrent nummular dermatitis can last for months or even years, with periods of improvement and flare-ups.
How is it diagnosed?
Nummular dermatitis is usually diagnosed based on a physical examination of the skin. The doctor will look at the characteristic coin-shaped lesions and ask about symptoms, medical history, and possible triggers. In some cases, the following may be used:
Skin Biopsy: A small sample of skin may be taken and examined under a microscope to rule out other conditions.
Allergy Testing: Patch testing or other allergy tests may be performed to identify potential allergens that may be contributing to the condition.
Timeline of Symptoms
The timeline of nummular dermatitis symptoms can vary, but a typical progression might be: 1. Initial Stage: Small, itchy bumps or papules appear on the skin. 2. Development: The bumps coalesce to form coin-shaped patches. 3. Inflammation: The patches become red, inflamed, and intensely itchy. 4. Weeping/Crusting: The patches may weep fluid or develop crusts, especially if scratched. 5. Scaling/Dryness: As the inflammation subsides, the patches may become dry and scaly. 6. Resolution (with treatment): The patches gradually fade and the skin returns to normal, although some discoloration (post-inflammatory hyperpigmentation or hypopigmentation) may remain temporarily.
Important Considerations
Secondary Infections: Scratching can lead to secondary bacterial infections, which require antibiotic treatment.
Post-Inflammatory Pigmentation Changes: After the patches heal, the skin may be temporarily darker (hyperpigmentation) or lighter (hypopigmentation).
Chronic Course: Nummular dermatitis can be a chronic condition with recurring flare-ups.
Differential Diagnosis: It's important to differentiate nummular dermatitis from other skin conditions such as ringworm (tinea corporis), psoriasis, contact dermatitis, and atopic dermatitis (eczema).
Sun Exposure: While some people find that sun exposure helps, others find that it worsens their nummular dermatitis. Use sunscreen and protective clothing if sun exposure triggers your condition.
Impact on Quality of Life: The intense itching and visible skin lesions can significantly impact quality of life, leading to sleep disturbances, anxiety, and depression. Addressing these issues is important.
Consultation with a Dermatologist: For persistent or severe cases, it's important to consult with a dermatologist for proper diagnosis and management.