Background:
Nummular eczema may mimic diseases that present with annular configuration and the
differential diagnosis is broad.
Objective:
This article aimed to provide an update on the evaluation, diagnosis, and treatment of nummular eczema.
Methods:
A PubMed search was performed in Clinical Queries using the key terms “nummular eczema”, “discoid
eczema”, OR “nummular dermatitis”. The search strategy included meta-analyses, randomized controlled trials, clinical
trials, observational studies, and reviews. The search was restricted to the English literature. The information retrieved
from the above search was used in the compilation of the present article. Patents were searched using the key terms
“nummular eczema”, “discoid eczema”, OR “nummular dermatitis” in www.google.com/patents and
www.freepatentsonline.com.
Results:
Nummular eczema is characterized by sharply defined, oval or coin-shaped, erythematous, eczematous plaques.
Typically, the size of the lesion varies from 1 to 10 cm in diameter. The lesions are usually multiple and symmetrically
distributed. Sites of predilection include the lower limbs followed by the upper limbs. The lesions are usually intensely
pruritic. The diagnosis is mainly clinical based on the characteristic round to oval erythematous plaques in a patient with
diffusely dry skin. Nummular eczema should be distinguished from other annular lesions. Dermoscopy can reveal
additional features that can be valuable for correct diagnosis. Biopsy or laboratory tests are generally not necessary.
However, a potassium hydroxide wet-mount examination of skin scrapings should be performed if tinea corporis is
suspected. Because contact allergy is common with nummular eczema, patch testing should be considered in patients with
chronic, recalcitrant nummular eczema. Avoidance of precipitating factors, optimal skin care, and high or ultra-high potency topical corticosteroids are the mainstay of therapy. Recent patents related to the management of nummular
eczema are also discussed.
Conclusion:
With proper treatment, nummular eczema can be cleared over a few weeks, although the course can be
chronic and characterized by relapses and remissions. Moisturizing of the skin and avoidance of identifiable exacerbating
factors such as hot water baths and harsh soaps may reduce the frequency of recurrence. Diseases that present with
annular lesions may mimic nummular eczema and the differential diagnosis is broad. As such, physicians must be familiar
with this condition so that an accurate diagnosis can be made, and appropriate treatment initiated.
Small annular lesions on the nose of a young Caucasian woman
