The condition may be mild until exacerbated by stressful life events, or symptoms may develop and slowly trend worse with time. Pathophysiology
Mast cell activation can be localized or systemic. MCAS can present with a wide range of symptoms in multiple body systems, these symptoms may range from digestive discomfort to chronic pain, mental issues as well as an anaphylactic reaction. Some examples of  tissue specific consequences of mast cell activation include urticaria, allergic rhinitis, and wheezing. Systemic mast cell activation presents with symptoms involving two or more organ systems (skin: urticaria, angioedema, and flushing; gastrointestinal: nausea, vomiting, diarrhea, and abdominal cramping; cardiovascular: hypotensive syncope or near syncope and tachycardia; respiratory: wheezing; naso-ocular: conjunctival injection, pruritus, and nasal stuffiness). This can result from the release of mediators from a specific site, such as the skin or mucosal tissue, or activation of mast cells around the vasculature. Diagnosis
MCAS is often difficult to identify due to the heterogeneity of symptoms and the "lack of flagrant acute presentation". Many of the numerous symptoms are non-specific in nature. Mast cell activation was assigned an ICD-10 code (D89.40, along with subtype codes D89.41-43 and D89.49) in October 2016.
Psoriasin may refer to:

Coal tar, by-product of the production of coke and coal gas from coal. S100A7, S100 calcium-binding protein A7.