Histaminergic angioedema

Angioedema affects deeper layers of skin or mucosal tissue, so swelling can feel tight, firm, or warm rather than like a surface welt. Histamine-driven episodes often occur with itchy hives and may affect the lips, eyelids, hands, feet, or face. The swelling can be uncomfortable and may develop quickly. Other forms of angioedema follow different pathways, so the pattern, medicines, family history, and accompanying hives matter during assessment. See [Angioedema](/conditions/angioedema/) and [Skin Swelling](/symptoms/skin-swelling/).

If swelling is limited to the skin and breathing is normal, contact a clinician promptly for an individual treatment plan. Use an antihistamine only as directed and check before combining products. Avoid a suspected trigger until reviewed, but do not stop an essential prescribed medicine without professional advice. Photograph the swelling and note its onset, location, hives, new foods, medicines, stings, or infections. [Antihistamine Treatment](/treatments/medical-dermatology/oral-antihistamine-therapy/) may be part of care; corticosteroids require clinician guidance.

Call emergency services immediately for tongue or throat swelling, hoarse voice, trouble swallowing, wheezing, breathlessness, dizziness, or faintness. Sit or lie safely while help is arranged and follow any emergency plan already prescribed. Do not rely on a rash disappearing if mouth or throat symptoms are present. Seek same-day review for rapidly increasing facial swelling, extensive swelling, or an episode that is new or unexplained.

Ask whether your episode fits histamine-driven angioedema, which triggers or medicines should be avoided, and what emergency steps apply to you. Ask how to distinguish a recurrence from a more serious reaction and whether family members need to know your plan.