Most papular urticaria is caused by the bites of bedbugs, mosquitoes, fleas, lice, mites, etc., and a few are associated with food allergies. Papular urticaria rash often occurs in batches, appearing in batches one after another, and is more common on the trunk and extensor sides of the limbs, clustered or scattered, and is usually not symmetrically distributed.
At the beginning of a slightly red papule, then mung bean or peanut size slightly fusiform red doughnut-like damage, some may have pseudopods, often with small blisters at the top, and some soon after the occurrence of hemispherical elevated tense blisters, the content of the clear, surrounded by no red halo. Pemphigus urticaria, on the other hand, is most common in the exposed parts of the limbs, lesions recur in batches, the distribution may not be symmetrical.
Pemphigus urticaria does not usually occur symmetrically, if the symptoms should be timely consultation, after the cause is clear and symptomatic treatment.