title: Effective treatment of pruritus in atopic dermatitis using H1 antihistamines (second-generation antihistamines): changes in blood histamine and tryptase levels.
abstract: BACKGROUND
  Atopic dermatitis (AD) is a common chronic inflammatory and allergic skin disease that almost always begins in childhood and follows a course of remittance and flare-up. AD is characterized by intense pruritus and itchiness that can be triggered by an interplay of genetic, immunologic and environmental factors. Of the mediators, histamine is one of the most potent inducers of pruritus. Serum tryptase, which is also a mediator, may be used to examine allergic disease as well. The development of minimal sedation H1 antihistamines (second-generation antihistamines) has revolutionized treatment of allergic diseases.
  
  
  OBJECTIVE
  The present study examines the efficacy of second-generation antihistamines in relieving pruritus due to AD. In addition, the relationship between AD pruritus and antihistamine therapy was analyzed by measuring the blood histamine and tryptase levels.
  
  
  METHODS
  Thirty-two AD patients were recruited and underwent second-generation antihistamine therapy for 2 weeks. Seventeen received combined topical corticosteroid treatment (Group 1) and the other 15 did not receive steroid treatment (Group 2). The Severity Index and Pruritus Score were assessed as an AD clinical activity index and compared with baseline data.
  
  
  RESULTS
  Both the Severity Index and Pruritus Score improved significantly in Group 1 (P<0.001, P<0.05). Group 2 demonstrated a significant improvement in Pruritus Score (P<0.05), but not in the Severity Index. Plasma histamine levels were significantly higher in AD at baseline compared with healthy controls.
  
  
  CONCLUSIONS
  Following antihistamine therapy, these levels decreased significantly in both AD groups (P<0.05). There was a significant correlation between baseline blood histamine and typtase levels. However, this correlation was not evident following treatment. This may reflect insufficient detection capabilities of the measuring assay. The present results suggest that second-generation antihistamine therapy provides an effective clinical treatment for AD, with a notable improvement in pruritus. Furthermore, antihistamine therapy reduced plasma histamine levels in AD patients. These findings further suggest that high blood histamine and tryptase levels in AD patients contribute to the pathogenesis of this disorder, including the onset of pruritus.
authors.affiliation: Department of Dermatology, St. Marianna University School of Medicine, 2-16-1 Sugao, Miyamae-ku, Kawasaki, Kanagawa 216-8511, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Imaizumi
authors.forename: Tamihiro
authors.initials: T
authors.lastname: Kawakami
authors.forename: Fumiko
authors.initials: F
authors.lastname: Murakami
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Soma
authors.forename: Masako
authors.initials: M
authors.lastname: Mizoguchi
mesh_terms: D000328:Adult; D003876:Dermatitis, Atopic / Q000150:complications*; D005260:Female; D006632:Histamine / Q000097:blood*; D006634:Histamine H1 Antagonists / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011537:Pruritus / Q000097:blood / Q000188:drug therapy* / Q000209:etiology*; D012697:Serine Endopeptidases / Q000097:blood*; D016896:Treatment Outcome; D053802:Tryptases
chemical_list: D006634:Histamine H1 Antagonists; D006632:Histamine; D012697:Serine Endopeptidases; D053802:Tryptases