Nummular dermatitis

Nummular Dermatitis

Nummular dermatitis on the arm

Nummular dermatitis, also known as nummular eczema, is a chronic inflammatory skin condition characterized by coin-shaped, itchy, and scaly patches. The term "nummular" is derived from the Latin word "nummus," meaning "coin," which describes the round appearance of the lesions.

Clinical Presentation

Nummular dermatitis typically presents as well-defined, round to oval erythematous plaques that are often pruritic. These lesions can appear anywhere on the body but are most commonly found on the arms, legs, and torso. The plaques may become crusted, weepy, or lichenified over time due to chronic scratching and irritation.

Pathophysiology

The exact cause of nummular dermatitis is not well understood, but it is believed to be a multifactorial condition involving genetic, environmental, and immunological factors. It is often associated with xerosis (dry skin) and may be exacerbated by environmental triggers such as cold weather, low humidity, and irritants like soaps and detergents.

Diagnosis

Diagnosis of nummular dermatitis is primarily clinical, based on the characteristic appearance of the lesions. A thorough history and physical examination are essential to differentiate it from other forms of eczema and dermatitis. In some cases, a skin biopsy may be performed to rule out other conditions such as psoriasis or tinea corporis.

Management

Management of nummular dermatitis involves a combination of lifestyle modifications, topical treatments, and, in some cases, systemic therapies. Key strategies include:

• Moisturization: Regular use of emollients to maintain skin hydration and barrier function.
• Topical Corticosteroids: Application of topical steroids to reduce inflammation and pruritus.
• Avoidance of Triggers: Identifying and avoiding potential irritants and allergens.
• Systemic Treatments: In severe cases, systemic corticosteroids or immunosuppressants may be considered.

Prognosis

Nummular dermatitis is a chronic condition with a tendency to recur. While it can be managed effectively with appropriate treatment, some individuals may experience persistent or recurrent episodes. Long-term management focuses on minimizing flare-ups and maintaining skin health.

Related Pages

• Eczema
• Atopic dermatitis
• Contact dermatitis
• Psoriasis