title: The efficacy of Prrrikweg gel in the treatment of insect bites: a double-blind, placebo-controlled clinical trial.
abstract: OBJECTIVE
  This study was conducted to examine the efficacy of Prrikweg gel, a homeopathic after-bite gel, in relieving the effects of mosquito bites, in particular itching and erythema.
  
  
  METHODS
  A double-blind, randomized, placebo-controlled clinical trial.
  
  
  METHODS
  London School of Hygiene and Tropical Medicine.
  
  
  METHODS
  100 healthy volunteers.
  
  
  METHODS
  All subjects were bitten under laboratory conditions by Aedes aegypti mosquitoes at one spot on the ventral aspect of the left forearm and another on a corresponding position on the right forearm. One spot was treated with the homeopathic after-bite gel and the other with a placebo gel.
  
  
  METHODS
  Itching was assessed on a 5-point discrete rating scale at 0, 0.5, 1, 26.5, and 48 h post-bite to compare the itch-relieving efficacy of the two treatments. Erythema development was assessed by photographing the bite sites, measuring length and width of the erythema with a calliper, and comparing the ratio of the erythema surface at baseline T(0) to the mean erythema surface at 0.5, 1, 26.5, and 48 h post-bite (T mean) for the two treatments.
  
  
  RESULTS
  Testing erythema development by comparing the ratio T(0)/T (mean, after-bite gel) and the ratio T(0)/T (mean, placebo gel) gave a two-tailed p = 0.098(95% Cl, -0.031-0.361) in favour of the after-bite gel. There was not a statistically significant difference between the itch relief provided by the two treatments (two-tailed p = 0.424; 95 percent Cl, -0.541-0.191). The correlation between itching and erythema was significant (r = 0.46; p < 0.001). CONCLUSIONS. There are strong indications that the homeopathic after-bite gel reduces erythema development following mosquito bites. The homeopathic mother tinctures of Echinacea angustifolia DC., Ledum palustre L., Urtica urens L. as well as the Hamamelis extract in this gel, whether alone or in combination, are the biologically active ingredients. The homeopathic after-bite gel was not demonstrated to relieve itching; however, based on the correlation between erythema and itching, an effect on itching is not inconceivable.
authors.affiliation: London School of Hygiene and Tropical Medicine, London, UK.
authors.forename: N
authors.initials: N
authors.lastname: Hill
authors.forename: C
authors.initials: C
authors.lastname: Stam
authors.forename: R A
authors.initials: RA
authors.lastname: van Haselen
mesh_terms: D000328:Adult; D004311:Double-Blind Method; D004890:Erythema / Q000188:drug therapy; D005260:Female; D005571:Formularies, Homeopathic as Topic; D005782:Gels; D006801:Humans; D007299:Insect Bites and Stings / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D011537:Pruritus / Q000188:drug therapy; D012867:Skin / Q000187:drug effects / Q000473:pathology; D013337:Students, Medical; D016896:Treatment Outcome
chemical_list: D005782:Gels; D010936:Plant Extracts