title: Comparison of skin test reactivity to histamine on back and forearm in young children.
abstract: BACKGROUND
  Skin responses to standardized positive and negative controls are important in the interpretation of a skin prick tests (SPT). However, this information in young children is lacking. We aimed to determine skin reactivity and compare the skin responses to these controls on the upper back and forearm in young children.
  
  
  METHODS
  SPTs for histamine hydrochloride 1 mg/ml (positive control) and 50% glycerol-saline (negative control) were performed on the upper back and forearm of children aged 6-25 months who came to the well-child clinic at Songklanagarind Hospital. SPTs to common allergens (cow's milk, soybean, egg white and house dust mite) were also evaluated.
  
  
  RESULTS
  A total of 133 children with a mean age of 12.4 months were enrolled in the study. Seventy-five children (56.4%) were male. The results from the upper back and the forearm of the histamine-induced mean wheal diameter + standard deviation (SD) were 4.74+1.37 mm and 3.86+1.82mm (p < 0.0001). The mean flare responses to histamine on the upper back and the forearm were 18.47 +/- 4.28 mm and 16.37 +/- 5.50 mm (p < 0.0001). The SPT results from the negative control on the upper back and forearm also had significant differences among the sizes of the wheal (0.57+1.17 vs. 0.34+0.89 mm, p = 0.007) and flare (4.57 +/- 3.04 mm vs. 3.34 +/- 1.91 mm, p < 0.0001).
  
  
  CONCLUSIONS
  Our study showed regional differences in wheal and flare responses to standardized positive and negative controls in young children. The upper back is more reactive than the forearm and is the preferred SPT site in young-aged children.
authors: Division of Allergy and Immunology, Department of Pediatrics, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla, Thailand. taraya@medicine.psu.ac.th
authors: Araya
authors: A
authors: Yuenyongviwat
authors: Duangrachanee
authors: D
authors: Koonrangsesomboon
authors: Pasuree
authors: P
authors: Sangsupawanich
mesh_terms: D001415:Back; D002675:Child, Preschool; D005260:Female; D005542:Forearm; D006632:Histamine / Q000008:administration & dosage* / Q000276:immunology; D017442:Histamine Agonists / Q000008:administration & dosage* / Q000276:immunology; D006801:Humans; D006967:Hypersensitivity / Q000175:diagnosis / Q000276:immunology*; D007223:Infant; D008297:Male; D012867:Skin / Q000276:immunology*; D012882:Skin Tests / Q000379:methods
chemical_list: D017442:Histamine Agonists; D006632:Histamine