Nummular dermatitis is one of the many forms of

dermatitis Dermatitis is inflammation of the skin, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened. The area of skin involved c ...

. it is characterized by round or oval-shaped itchy lesions. The name comes from the Latin word " nummus," which means "coin."

Signs and symptoms

Nummular dermatitis is characterized by chronic or relapsing itchy coin-sized

ovoid An oval () is a closed curve in a plane which resembles the outline of an egg. The term is not very specific, but in some areas ( projective geometry, technical drawing, etc.) it is given a more precise definition, which may include either o ...

-shaped red plaques. They can occur on the trunk, limbs, face, and hands.

Causes

Many contact sensitizers or irritants are known to cause

contact dermatitis Contact dermatitis is a type of acute or chronic inflammation of the skin caused by exposure to chemical or physical agents. Symptoms of contact dermatitis can include itchy or dry skin, a red rash, bumps, blisters, or swelling. These rashes are ...

superimposed on nummular dermatitis. Studies have implicated nickel, cobalt, chromate, and fragrance as likely culprits. Xerosis, or dehydration of skin is also a likely cause. Infection with ''

Staphylococcus aureus ''Staphylococcus aureus'' is a Gram-positive spherically shaped bacterium, a member of the Bacillota, and is a usual member of the microbiota of the body, frequently found in the upper respiratory tract and on the skin. It is often posit ...

'' bacteria or ''

Candida albicans ''Candida albicans'' is an opportunistic pathogenic yeast that is a common member of the human gut flora. It can also survive outside the human body. It is detected in the gastrointestinal tract and mouth in 40–60% of healthy adults. It is usu ...

'' may also play a role.

Diagnosis

Diagnosis of nummular dermatitis is largely via clinical observation. Biopsies are typically not necessary, and cannot be used to rule out other atopic dermatitis or other eczemas. However, patch testing may be employed to rule out irritants (

) as a cause. In children, nummular dermatitis is commonly confused with

tinea corporis Tinea corporis is a fungal infection of the body, similar to other forms of tinea. Specifically, it is a type of dermatophytosis (or ringworm) that appears on the arms and legs, especially on glabrous skin; however, it may occur on any superficial ...

Treatment

One of the keys to treatment and prevention involves keeping the skin moisturized.

Lotion Lotion is a low-viscosity topical preparation intended for application to the skin. By contrast, creams and gels have higher viscosity, typically due to lower water content. Lotions are applied to external skin with bare hands, a brush, a clean ...

s, creams, and bath oils may help prevent an outbreak. If the condition flares up, a common treatment involves the application of topical

corticosteroid Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are inv ...

s. Oral

antihistamine Antihistamines are drugs which treat allergic rhinitis, common cold, influenza, and other allergies. Typically, people take antihistamines as an inexpensive, generic (not patented) drug that can be bought without a prescription and provide ...

s may help lessen itching. Avoidance of irritants is a common strategy. More severe cases sometimes respond to

ultraviolet light Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiatio ...

treatment. If the condition occurs only during the sun-less winter months then vitamin D supplement might be an effective treatment.

Epidemiology

The prevalence of nummular dermatitis in the United States is approximately 2 per 1,000. It is considered a disease of adulthood, for it is rare in children.

References

External links

{{DEFAULTSORT:Nummular Dermatitis Eczema