Development of the symptomatic dermographism quality of life questionnaire

Symptomatic Dermographism (SD), also known as "urticaria factitia", is the most common subtype of chronic inducible urticaria. Affected patients develop itch and strip-shaped wheals that usually last for 30 min after minor stroking, rubbing, or scratching of the skin. The quality of life (QoL) of patients with SD is often strongly affected. However, a QoL instrument to properly assess this impairment is not yet available.

The aim of this study was to develop the first disease-specific patient reported outcome measure|patient reported outcome measures (PROM) to evaluate QoL impairment in SD patients, the Symptomatic Dermographism Quality of Life Questionnaire (SD-QoL).

SD-QoL was developed following current guidelines for PROM development. We first generated a hypothetical conceptional framework of the SD-QoL, followed by an item generation and an item selection/reduction phase.

During the item generation phase, 69 potential items of the SD-QoL were generated by applying a combined approach consisting of literature review, expert input as well as semi-structured interviews with affected patients. During the item selection phase, we reduced this long list of items to a final 13-item set by means of impact analysis, inter-item correlation, and additional criteria for item reduction, including an expert review for content (face) validity. Finally, a US-American-English version of the SD-QoL was developed using a structured translation process.

The SD-QoL is the first disease-specific-QoL instrument for SD with a recall period of 7 days that allows the assessment of QoL in SD patients. A subsequent validation study will determine its validity and reliability.