Triggers and causes.
Other illnesses such as infections are sometimes associated with CU, i.e. it has been determined that certain diseases appear more commonly in patients with CU than in healthy ones. Often – but certainly not always – the CU disappears following successful treatment of the associated illness. It should not be a surprise then that CU patients frequently suffer from several urticaria diseases simultaneously. Roughly one in four CU patients suffers from an additional form of urticaria (cholinergic urticaria, chronic urticaria, dermogrpahic). Food allergies, exercise-induced asthma, hypersensitive reactions to insect venom (i.e. insects, jellyfish) and atopy also occur more frequently in CU patients.
CU furthermore appears to also be associated with infectious diseases. Often mentioned in this vein are infectious mononucleosis, syphilis, hepatitis, measles, chicken pox, Lyme disease, HIV infections, respiratory tract infections, Helicobacter pylori (a germ that can cause ulcers in the upper gastrointestinal tract) and parasitic diseases. Inflammatory processes in the ear/nose/throat area, in the tooth and jaw area or in the urogenital tract can be associated with CU and perpetuate it. That could also explain why many CU patients are cured of their CU following antibiotic therapy.
Cryoglobulinaemia are also more common in CU patients than in a control group. Cryoglobulins are blood proteins that become gelatinous at normal body temperatures and therefore lead to an increased viscosity of the blood, i.e. the blood becomes stickier. The symptoms typically begin with the fingertips, which then evince circulatory problems when exposed to cold in particular. Cryoglobulins are generated particularly frequently with chronic viral infections, although malignant illnesses or blood diseases could potentially underlie them as well.
Drugs can also be a trigger for a CU. This includes the 'usual suspects' like acetylsalicylic acid (e.g. in Aspirin®), Diclofenac, Indometacin, Ibuprofen, Metamizol and the ACE inhibitors. But oral contraceptives ("the pill"), anti-fungal agents or antibiotics are also potential triggers.