Symptoms

As with other forms of urticaria, the main symptoms of dermographic urticaria are temporary wheals, flaring and itchiness. Less common are prickles, stinging and heat sensitivity. With dermographic urticaria, skin manifestations never appear spontaneously. They only occur at those locations where shearing force was applied; this can be spots where tight clothing rubbed against the skin or that were scratched. The strength of the shearing forces required to trigger the event varies greatly. For some patients a light stroke is enough, while others require strong scratching before the skin changes are triggered.

The wheals associated with dermographic urticaria form within 5 minutes and can last up to several hours. The following is a brief summary of the sequence of the easily observable skin reactions: Following the rubbing or scratching of the skin, the skin then reddens (through increased blood flow), which is followed by the formation of a reddened flare extending far beyond the trigger spot. A wheal then forms there and itchiness ensues. The wheal is initially still red. It then turns a whitish colour and after a few minutes achieves its complete picture: an itchy, whitish wheal that extends somewhat beyond the triggering spot, surrounded by a reddened flare. The symptoms then disappear in the same order as they appeared: the flare fades after a short period, and then itchiness subsides and disappears together with the wheal.