Background: Pharmacologic studies in atopic eczema (AE) are difficult to standardize. Patients with AE differ in the stage of their skin disease (acute, subacute, chronic). Objective: This study was designed to assess macroscopic and microscopic effects of pretreatment with topical glucocortico-steroids (GCSs) and tar on the atopy patch test (APT) reaction in patients with atopic eczema. Methods: Nonlesional skin of the back of patients with AE (n = 6) was treated for 3 weeks at 3 different sites with triamcin-olonacetonide 0.1% in cetamacrogol ointment (GCSs), pix liquida 10% in cetamacrogol ointment (tar), and cetamacrogol ointment (vehicle), respectively. APTs were performed, and biopsy specimens were taken from all these sites (time = 0 and 24 hours) for immunohistochemical analysis. Results: Treatment with both GCSs and tar was able to reduce the macroscopic outcome of the APT reaction. Furthermore, both treatment modalities had an almost equally inhibiting effect on the influx of T cells, eosinophils, and CD1⁺, RFD1⁺, IFN-γ⁺, and IL-4⁺ cells, as well as on the percentage of vessels expressing the adhesion molecules vascular cell adhesion molecule 1 and E-selectin in response to epicutaneous aeroallergen challenge. Conclusion: Although both treatments significantly reduced the various cellular constituents of allergic inflammation, all cell types remained present. In addition, this study shows that the APT can be used to evaluate the effect of topical anti-inflammatory treatments on allergic inflammation in patients with AE. (J Allergy Clin Immunol 2000;106:737-43.)