<b><i>Background:</i></b> Allergic contact dermatitis (ACD) is an inflammatory skin disease caused by repeated skin exposure to contact allergens. The severity and duration of this disease are associated with many different factors. Some of these factors may represent markers for monitoring disease activity and the individual response to an intervention. <b><i>Methods:</i></b> We used a targeted metabolomics approach to find such factors in the serum of individuals with ACD. Metabolomics profiles were examined and compared in the acute phase of the disease and also in the absence of disease activity. <b><i>Results:</i></b> Our study identified a significant remission phase of ACD-associated systemic biochemical shifts in 2 metabolic pathways: tryptophan-kynurenine and phenylalanine-tyrosine. <b><i>Conclusions:</i></b> Although the responsible mechanisms are unclear, these results suggest that the remission phase of ACD is linked to tryptophan metabolism via kynurenine and phenylalanine-tyrosine pathways. However, further replication studies with a larger number of subjects and their subgroups are necessary to validate our results. These studies may provide a new perspective with which to understand the mechanism of and find potential biomarkers of ACD, as well as a new reference for personalized treatment.