Swelling without wheals can follow a different mechanism

Bradykinin-mediated angioedema is considered when episodic swelling occurs without hives or typical treatment response.

Hereditary C1-inhibitor deficiency or dysfunctionRecurrent swelling without wheals plus abdominal attacks can justify C4 and C1-inhibitor evaluation.
Acquired C1-inhibitor deficiencyLater-onset recurrent nonurticarial swelling can have a different underlying cause.
ACE-inhibitor-associated angioedemaCertain blood-pressure medicines can cause swelling through bradykinin pathways.
Other local causes of swellingDental, venous or inflammatory problems can mimic angioedema in particular sites.

Repeated abdominal attacks can be part of an angioedema pattern

Some angioedema syndromes affect the bowel wall and cause severe episodic abdominal pain.

Hereditary C1-inhibitor deficiency or dysfunctionRecurrent swelling without wheals plus abdominal attacks can justify C4 and C1-inhibitor evaluation.
Acquired C1-inhibitor deficiencyLater-onset recurrent nonurticarial swelling can have a different underlying cause.
Mast-cell-mediated angioedemaItchy hives accompanying swelling may favor a histamine-related mechanism.
ACE-inhibitor-associated angioedemaCertain blood-pressure medicines can cause swelling through bradykinin pathways.

ACE-inhibitor-related angioedema may occur even after prolonged use and requires clinician-directed medication assessment.

ACE-inhibitor-associated angioedemaCertain blood-pressure medicines can cause swelling through bradykinin pathways.
Hereditary C1-inhibitor deficiency or dysfunctionRecurrent swelling without wheals plus abdominal attacks can justify C4 and C1-inhibitor evaluation.
Acquired C1-inhibitor deficiencyLater-onset recurrent nonurticarial swelling can have a different underlying cause.
Other medication-associated swellingTiming of NSAIDs or other medicines can be informative.

Hives and an antihistamine response may suggest a mast-cell-mediated pathway, though they do not prove its cause.

Mast-cell-mediated angioedemaItchy hives accompanying swelling may favor a histamine-related mechanism.
Other medication-associated swellingTiming of NSAIDs or other medicines can be informative.
Other local causes of swellingDental, venous or inflammatory problems can mimic angioedema in particular sites.
Hereditary C1-inhibitor deficiency or dysfunctionRecurrent swelling without wheals plus abdominal attacks can justify C4 and C1-inhibitor evaluation.