A systemic disease is one that affects the entire body or multiple organs, rather than just one localized area. The disease processes occur throughout the entire body and can cause a wide variety of symptoms. Examples of systemic diseases include diabetes and rheumatoid arthritis.
Chronic spontaneous urticaria (CSU) is often thought of as a skin condition, but it actually involves specialized immune cells all throughout the body, not just the skin. That's why it's considered a systemic disease.
These specialized immune cells, called mast cells, play a key role in CSU.1 These cells are part of your body's normal defense system and are found in many tissues throughout the body, including the skin. When activated, mast cells release a substance called histamine into these nearby tissues - this causes the visible symptoms of urticaria, like redness, itching, or swelling.2
In CSU, mast cells get activated when the immune system mistakenly reacts to harmless substances, or even to the body's own tissues. This overreaction triggers mast cells to release histamine when they shouldn't. In about half of CSU cases, this process is autoimmune, meaning the body reacts against itself.
Since mast cells are so concentrated in the skin, urticaria symptoms like itching, redness, and swelling are most noticeable there.2 However, mast cells are also found in other areas of the body, such as the intestinal lining, which explains why symptoms can sometimes affect more than just the skin.
You deserve more - don’t let chronic spontaneous urticaria control your life. Ask your doctors about clear skin and zero itch.
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- Friedman A, et al. Dermatol Ther (Heidelb) 2024;14(6):1371-1387.
- Metcalfe DD, et al. Physiol Rev 1997;77(4).