Certain medications can cause mast cell degranulation and should be avoided if there is extensive urticaria pigmentosa. The appearance of urticaria pigmentosa is generally so characteristic that no specific tests are necessary. However, occasionally a skin biopsy is needed to confirm the diagnosis. However the following can be helpful. Potent steroid creams applied for several months under occlusion can reduce itching and unsightliness, but the patches tend to recur within a few months.
Topical steroids are only suitable for limited areas.
This form of ultraviolet radiation is the most effective treatment for adults with urticaria pigmentosa. Two or three treatments each week are required for several months. PUVA lessens the itch and improves the appearance. The urticaria pigmentosa is likely to recur within six to twelve months but the treatment can be repeated.