Impact of patch testing on dermatology-specific quality of life in patients with allergic contact dermatitis

A dermatology-specific quality-of-life instrument has been created and validated for its sensitivity, reproducibility, content, and construct validity. This instrument was used in an observational prospective study that evaluated the cost-effectiveness of patch testing in patients with contact dermatitis and suspicion of allergic component.

This multicenter, prospective, observational study was designed to study the various direct and indirect costs associated with diagnosis and treatment of suspected allergic contact dermatitis and the benefits of diagnosis with and without patch testing. The costs and benefits of various methods of diagnosis are evaluated to determine if patch testing is more cost-effective as a diagnostic method. One of the outcomes evaluated was the quality of life of the participants in the study and the impact of patch testing on this cohort.

A total of 567 subjects were enrolled to obtain evaluable data from at least 500 subjects from ten study centers; the investigators were chosen so as to obtain a mix of stratified degrees of usage of patch testing. Data were collected on demographics, physical characteristics, history of disease, visits to physicians, and, to evaluate costs, the use of resources such as drugs, nondrug substances, and services; other outcome data collected were on physician evaluation of improvement, confirmation of diagnosis, physician opinion of the disease management, and patient evaluation of dermatology-specific quality of life (DSQL), and pertinent economic factors. Only 6-month and 12-month follow-up visits were mandatorily scheduled according to the protocol; however, participants and providers were free to arrange additional visits as deemed necessary for health care.

This report focuses on the evaluations at the 6-month follow-up. There are completely evaluable data on pharmacoeconomics and DSQL for 431 patients. About 43% were patch tested, and the rest were diagnosed using the information from history and physical examinations. There was significantly better improvement in each of the DSQL domains in patch tested subjects compared with non-patch-tested subjects. In addition, patients treated in "low" use clinics had lower quality of life at 6-month follow-up than those treated in "high" use clinics.

Patch testing helps to diagnose the etiology of contact dermatitis early and treat the disease before it becomes chronic, thus reducing resources used and improving patient quality of life considerably.