Nummular dermatitis (commonly known as nummular eczemaordiscoid eczema) is one of the many forms of dermatitis.[1] It is characterized by round or oval-shaped itchy lesions.[2] The name comes from the Latin word "nummus," which means "coin."
Nummular dermatitis is characterized by chronic or relapsing itchy coin-sized ovoid-shaped red plaques.[3][4] They can occur on the trunk, limbs, face, and hands.[1][2][5]
Many contact sensitizers or irritants are known to cause contact dermatitis superimposed on nummular dermatitis. Studies have implicated nickel, cobalt, chromate, and fragrance as likely culprits.[6][7]Xerosis, or dehydration of skin is also a likely cause.[8] Infection with Staphylococcus aureus bacteria or Candida albicans may also play a role.[8]
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.[9][10] However, patch testing may be employed to rule out irritants (contact dermatitis) as a cause.[6][11] In children, nummular dermatitis is commonly confused with tinea corporis.[8]
One of the keys to treatment and prevention involves keeping the skin moisturized. Lotions, creams, and bath oils may help prevent an outbreak. If the condition flares up, a common treatment involves the application of topical corticosteroids. Oral antihistamines may help lessen itching. Avoidance of irritants is a common strategy. More severe cases sometimes respond to ultraviolet light treatment. If the condition occurs only during the sun-less winter months then vitamin D supplement might be an effective treatment.[citation needed]
The prevalence of nummular dermatitis in the United States is approximately 2 per 1,000.[12] It is considered a disease of adulthood, for it is rare in children.[13]
^ abCowan MA (1961-01-01). "Nummular eczema. A review, follow-up and analysis of a series of 325 cases". Acta Dermato-Venereologica. 41: 453–460. PMID13881857.
^ abWeidman AI, Sawicky HH (January 1956). "Nummular eczema; review of the literature: survey of 516 case records and follow-up of 125 patients". A.M.A. Archives of Dermatology. 73 (1): 58–65. doi:10.1001/archderm.1956.01550010060006. PMID13275125.
^Adachi A, Horikawa T, Takashima T, Ichihashi M (August 2000). "Mercury-induced nummular dermatitis". Journal of the American Academy of Dermatology. 43 (2 Pt 2): 383–385. doi:10.1067/mjd.2000.102457. PMID10901730.
^ abcWilliams HC (June 2005). "Clinical practice. Atopic dermatitis". The New England Journal of Medicine. 352 (22): 2314–2324. doi:10.1056/NEJMcp042803. PMID15930422.
^Kulthanan K, Samutrapong P, Jiamton S, Tuchinda P (December 2007). "Adult-onset atopic dermatitis: a cross-sectional study of natural history and clinical manifestation". Asian Pacific Journal of Allergy and Immunology. 25 (4): 207–214. PMID18402293.
^Julián-Gónzalez RE, Orozco-Covarrubias L, Durán-McKinster C, Palacios-Lopez C, Ruiz-Maldonado R, Sáez-de-Ocariz M (2012-09-01). "Less common clinical manifestations of atopic dermatitis: prevalence by age". Pediatric Dermatology. 29 (5): 580–583. doi:10.1111/j.1525-1470.2012.01739.x. PMID22469300. S2CID5339404.
