title: Unilateral laterothoracic exanthem. A clinicopathologic study of forty-eight patients.
abstract: BACKGROUND
  Four years ago, we began seeing young children with an unusual, predominantly unilateral, morbilliform and eczematous, self-limited cutaneous eruption. It appeared to correspond to unilateral laterothoracic exanthem (ULE) reported from France and to an eruption described as "a new papular erythema of childhood" in the United States.
  
  
  OBJECTIVE
  We conducted a prospective study of ULE to define its clinical evolution, pathology, and therapy. In addition, we performed epidemiologic and microbiologic investigations in an attempt to determine the cause of ULE.
  
  
  METHODS
  We studied 48 children with ULE. In some patients, blood, urine, stool, as well as skin biopsy specimens were analyzed.
  
  
  RESULTS
  ULE is a morbilliform, eczematous eruption that often begins close to the axilla and spreads to become bilateral, although it usually retains a unilateral predominance. Patients' mean age at onset is 24.3 months, with a female predominance (2:1) and mean duration of 5 weeks, followed by spontaneous resolution that may or may not be improved with topical corticosteroids. It is characterized by a unique eccrine lymphocytic infiltration. Although signs of infection were reported by most patients, no one infectious agent was identified. No significant epidemiologic factor was found.
  
  
  CONCLUSIONS
  ULE, in young children, is a self-limited morbilliform and scarlatiniform eruption that may represent a specific skin reaction to one or more infectious agents.
authors.affiliation: Department of Pediatrics, Hôpital Sainte-Justine, Montreal, Quebec, Canada.
authors.forename: C C
authors.initials: CC
authors.lastname: McCuaig
authors.forename: P
authors.initials: P
authors.lastname: Russo
authors.forename: J
authors.initials: J
authors.lastname: Powell
authors.forename: L
authors.initials: L
authors.lastname: Pedneault
authors.forename: P
authors.initials: P
authors.lastname: Lebel
authors.forename: D
authors.initials: D
authors.lastname: Marcoux
mesh_terms: D000287:Administration, Topical; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D001365:Axilla; D001706:Biopsy; D002675:Child, Preschool; D003879:Dermatologic Agents / Q000627:therapeutic use; D004439:Eccrine Glands / Q000473:pathology; D004485:Eczema / Q000188:drug therapy / Q000382:microbiology / Q000473:pathology; D004890:Erythema / Q000188:drug therapy / Q000382:microbiology / Q000473:pathology; D005076:Exanthema / Q000188:drug therapy / Q000473:pathology* / Q000503:physiopathology; D005260:Female; D005938:Glucocorticoids; D006801:Humans; D007223:Infant; D008214:Lymphocytes / Q000473:pathology; D008297:Male; D011446:Prospective Studies; D011792:Quebec; D012075:Remission, Spontaneous; D012737:Sex Factors; D012867:Skin / Q000473:pathology; D013909:Thorax
chemical_list: D000893:Anti-Inflammatory Agents; D003879:Dermatologic Agents; D005938:Glucocorticoids