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Hereditary angioedema is caused by an inherited absence of a protein called C1 inhibitor, which leads to deep tissue swelling. Similar symptoms are seen with allergic angioedema, which is caused by an allergic reaction. There are a number of other allergic and non-allergic skin conditions that are related to angioedema including:

• Eczema. Inflammatory skin disease with lesions that usually appear very dry, thickened or scaly. Contact dermatitis is one form of eczema associated with angioedema. It is a skin rash that is the result of direct contact between an allergen or irritant and the skin.
  
  

  

• Hives. Red, swollen patches of skin that occur in groups and may burn, sting or itch. Hives sometimes accompany angioedema. In general, hives are more common and less severe than angioedema. 
  
  
• Skin rashes. Any change in the color and/or texture of the skin (e.g., redness, itching, inflammation and raised bumps).