This paper presents radiological and biochemical investigations facilitating the diagnosis of possible systemic involvement in 9 patients with urticaria pigmentosa. The study included: ultrasound examination, CT scan of the abdominal cavity, radiograms of the chest and the lumbosacral part of the spinal column, as well as the evaluation of histamine, methylhistamine and methylimidazoleacetic acid levels in the 24 hour urine collection. In one out of nine patients, numerous enlarged lymph nodes were found in the abdominal cavity. The same patient also showed highly increased levels of histamine and its metabolites in the urine. On the grounds of our study, we conclude that additional biochemical and radiological examinations should be performed in each adult patient with urticaria pigmentosa in order to detect any possible systemic changes.

Keywords: systemic mastocytosis, Urticaria Pigmentosa, mast cell, Histamine, radiologic imaging