Drug-induced nummular dermatitis.

What is nummular? dermatitis?

Nummular dermatitis is common inflammatory skin disorder. Also known as nummular eczema, discoid eczema or discoid dermatitis due to its distinctive disc-shaped lesions. It can also be called exudative or nummular neurodermatitis. eczematous dermatitis.

What is drug-induced nummular dermatitis?

The drug-induced form of nummular dermatitis is diagnosed when its onset is associated with certain medications.

Who gets drug-induced nummular dermatitis?

Drug-induced nummular dermatitis has similar risk factors to the non-drug-induced form of nummular dermatitis; These include:

• Sex – occurs more frequently in men than in women
• Age: it occurs more frequently in men between 60 and 70 years old and in women between 20 and 30 years old.
• Existing dermatitis, especially a history of dry skin or stasis dermatitis
• A skin injury, such as thermal burns, chemical burns, cuts, abrasions, or insect bites.
• Cold and dry climate.

What causes drug-induced nummular dermatitis?

Nummular dermatitis can be caused by medications that affect the function of the epidermal barrier or immune response. Medications that can cause excessive skin dryness and dermatitis include:

• Diuretics
• Statins
• Immunomodulatory drugs
  • Interferon
  • Ribavirin
  • Intravenous immunoglobulin
  • Tumor necrosis factor (TNF) inhibitors.

What are the clinical characteristics of nummular dermatitis?

Nummular dermatitis presents with bilateral, well defined circular, oval or disc-shaped erythematous plates. They can be dry or exudative (slimy).

• The plates are usually several centimeters in diameter.
• They usually appear on the extremities, trunk or feet of the individual.
• The plaques may be erythematous or bluish-purple; They can then be flattened to hyperpigmented macules.
• Yellowish crust is associated with Staphylococcus aureus colonization or infection.
• Pruritus It can be intense, to the point of disturbing sleep.
• Scratching can cause lichen simplex chronicus, especially on the extremities, scalp, or scrotum.

How is drug-induced nummular dermatitis diagnosed?

The diagnosis of drug-induced nummular dermatitis is based on taking a careful patient history and physical examination. Additional investigations may include:

• Swabs for bacterial culture
• Patch tests, if contact allergy It is a possible cause of dermatitis.

How is drug-induced nummular dermatitis treated?

Treatments for nummular dermatitis aim to rehydrate the skin and repair the epidermal barrier. Treatment may include:

• Warm baths or showers with a soap-free cleanser
• Emollients

• Antibiotics to treat bacterial infections. [Link to Bacterial skin infections]

• Current corticosteroids
• Phototherapy

• Immunomodulatory medications, such as methotrexate.

What is the outcome of drug-induced nummular dermatitis?

Nummular dermatitis can take months or sometimes years to resolve. When drug-induced, it may disappear more quickly cessation of the medication that caused the appearance of dermatitis.