Nummular dermatitis

Nummular dermatitis
Nummular dermatitis
Other names	Discoid dermatitis, Discoid eczema, Microbial eczema, Nummular eczema, Nummular neurodermatitis
	Lesions visible on outer thigh
Specialty	Dermatology
Differential diagnosis	Dermatophytosis (Ringworm)

Nummular dermatitis (commonly known as nummular eczema or discoid 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."

Signs and symptoms

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]

Causes

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

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]

Treatment

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]}

Epidemiology

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]

References

^ ^a ^b Cowan MA (1961-01-01). "Nummular eczema. A review, follow-up and analysis of a series of 325 cases". Acta Dermato-Venereologica. 41: 453–460. PMID 13881857.
^ ^a ^b Weidman 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. PMID 13275125.
^ 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. PMID 10901730.
^ Rollins TG (October 1968). "From xerosis to nummular dermatitis. The dehydration dermatosis". JAMA. 206 (3): 637. doi:10.1001/jama.1968.03150030093022. PMID 5695586.
^ Perry AD, Trafeli JP (2009-05-01). "Hand dermatitis: review of etiology, diagnosis, and treatment". Journal of the American Board of Family Medicine. 22 (3): 325–330. doi:10.3122/jabfm.2009.03.080118. PMID 19429739.
^ ^a ^b Khurana S, Jain VK, Aggarwal K, Gupta S (December 2002). "Patch testing in discoid eczema". The Journal of Dermatology. 29 (12): 763–767. doi:10.1111/j.1346-8138.2002.tb00219.x. PMID 12532040. S2CID 43205871.
^ Bonamonte D, Foti C, Vestita M, Ranieri LD, Angelini G (2012). "Nummular eczema and contact allergy: a retrospective study". Dermatitis. 23 (4): 153–157. doi:10.1097/der.0b013e318260d5a0. PMID 22828253. S2CID 446758.
^ ^a ^b ^c Williams HC (June 2005). "Clinical practice. Atopic dermatitis". The New England Journal of Medicine. 352 (22): 2314–2324. doi:10.1056/NEJMcp042803. PMID 15930422.
^ 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. PMID 18402293.
^ 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. PMID 22469300. S2CID 5339404.
^ Krupa Shankar DS, Shrestha S (2005-11-01). "Relevance of patch testing in patients with nummular dermatitis". Indian Journal of Dermatology, Venereology and Leprology. 71 (6): 406–408. doi:10.4103/0378-6323.18945. hdl:1807/5587. PMID 16394482.
^ Johnson ML, Roberts J (1977-01-01). "Prevalence of dermatological disease among persons 1-74 years of age: United States". ADV Data Natl CTR Health Statistics.
^ Krol A, Krafchik B (2006-03-01). "The differential diagnosis of atopic dermatitis in childhood". Dermatologic Therapy. 19 (2): 73–82. doi:10.1111/j.1529-8019.2006.00058.x. PMID 16669989. S2CID 42426282.