Validity of Skin Prick Test toward House Dust Mite and House Dust Immunoglobulin E RAST in Atopic Dermatitis

In extrinsic type atopic dermatitis (AD) there is an increased of specific immunoglobulin (IgE) towards house dust mites (HDM) and house dust (HD), resulting in positive skin prick test (SPT). The method of this study was cross sectional, analytic-observational, to find validity of SPT toward HDM and HD IgE radioallergosorbent (RAST) in AD patients. The study was held from August to November 2011 in Department of Dermatovenereology Dr. Hasan Sadikin Hospital Bandung. Spearman's rank correlation coefficient was used for statistical analysis. The results showed positive SPT to HDM in AD patients were statistically significant higher than non-AD. Positive SPT to HD in AD patients were higher than non-AD but statistically non significant. Value of HDM SPT positivity and IgE RAST in AD was directly proportional, but not with HD. There was a higher positivity of HMD SPT in AD patients (15/16) than in non-AD (5/16). Positivity value of HDM SPT was proportional to the HDM IgE RAST in AD patients with Spearman's Rank correlation coefficient 0.541 (p=0.031). The results of HDM SPT toward HDM IgE RAST in AD patients showed higher validity sensitivity, specificity, and accuracy, 100%, 25% and 81% respectively, while HD SPT toward HD IgE RAST with sensitivity, specificity, and accuracy 43%, 78% and 63% respectively. In conclusions, HDM TDR examination could be used as a marker for AD diagnosis, due to positive HDM TDR examination result could give a meaning of increased specific IgE with RAST IgE examination.