D2.234 - Mimicry of delayed pressure urticaria. Clinical case reports

Case 1, 39 y.o., reported episodes of edema last 1.5 years several times a week, accompanied by itching, the symptoms resolved within 2-3 days. Skin rashes had never occurred. Family history is unremarkable. Complement component disorder is suspected but not confirmed by laboratory tests.  C4 0.28 g/l (0.15-0.57), C1q antibody negative.Several episodes of hospitalization with the need for dexamethasone, with plasmapheresis due to the low effectiveness of systemic steroids. Antihistamines at standard and double doses were ineffective. Antiparasitic therapy and Helicobacter eradication were also performed, but symptoms remained unchanged.The location of the swelling was noteworthy –including the cheeks, fingers, extremities, buttocks, and lips. A detailed interview revealed a correlation between the swelling and the previous skin compression. With levocetirizine therapy at an escalating dose of 20 mg/day, the symptoms regressed completely within two days of starting therapy.

Case 2, 42 y. o., noted a tendency to swelling since childhood. Since 2018, experienced swelling of the fingers during prolonged exertion, sports activities with equipment. Since 2023, symptoms increased in severity and frequency: swelling of the feet and face,weakness, fatigue, and arthralgia.120 mg of fexofenadine - ineffective.  CCP, RF, DNA antibodies, ANF, HLA B27, ANA immunoblot, C4, C1 inhibitors are within reference limits, IgE is 82 IU/mL (<100). CRP is 16.5, ESR is 17. During examination, the location of the swelling is noteworthy – any areas of the skin subjected to compression. A test was performed: 7 kg bag  for 15 minutes. After 90 minutes, swelling and hyperemia developed at the site of pressure. Fexofenadine 180 mg at a double dose - complete control of the urticaria.

Delayed pressure urticaria is relatively rare in isolation, so there are no population-based epidemiological data. A low incidence of the disease has also been described among all types of urticaria—from 0.7 to 3.5%. These clinical cases demonstrate the difficulties of diagnosis due to the delayed onset of symptoms and their prolonged regression, which is uncharacteristic of urticaria, the variety of clinical manifestations, the possible presence of systemic symptoms, and elevated markers of a systemic inflammatory response.