Urticaria: red welts and itching
Quick facts
- Definition
- Skin reaction with raised, reddish, itchy welts that appear and disappear.
- Common name
- Hives, skin allergy, welts.
- Duration
- Each welt usually lasts hours; acute if it lasts less than 6 weeks, chronic if it goes beyond that.
- Relation
- May come with angioedema, which is swelling of deeper layers.
- Warning sign
- Shortness of breath, hoarseness, swelling of the tongue or throat and a drop in blood pressure.
Urticaria is a skin reaction in which raised, reddish or pink welts appear, usually itchy, that come and go within hours and can move from place to place. In everyday language, they are "hives" or "welts". It is caused by the release of substances, such as histamine, by skin and vessel cells, which makes fluid leak out and causes superficial swelling.
What are the types?
- Acute: lasts less than six weeks; it may be linked to infections, medications, foods or contact.
- Chronic: persists for six weeks or more; the cause is often not found.
- Inducible: appears after physical stimuli such as pressure, cold, heat or friction.
When it reaches deeper layers of the skin, angioedema forms, a more diffuse swelling common on the lips and eyelids. The two conditions can coexist.
Why does it matter in an HOF clinic?
In the medical history, asking about allergies and previous urticaria is mandatory. A person with chronic urticaria or active flare-ups may have more frequent reactions and make it harder to interpret signs after a procedure. It is also important to tell urticaria apart from an expected local reaction, such as swelling and redness at the injection point.
| Aspect | Expected local reaction | Urticaria |
|---|---|---|
| Location | Treated area | May appear in several places |
| Appearance | Redness and swelling | Raised welts that move around |
| Itching | Variable | Typical |
| Duration | Days | Each welt lasts hours |
When is it an emergency?
Urticaria can be part of a systemic allergic reaction. Shortness of breath, wheezing, hoarseness, swelling of the tongue or throat, dizziness, a drop in blood pressure or a feeling of fainting are signs of severe hypersensitivity and require immediate emergency care. The clinic should have a protocol for this scenario and the team should know how to activate it.
Urticaria and injectable products
Hypersensitivity reactions to fillers and other products are described, although uncommon. It is up to the professional to assess, case by case, the patient's history and the need for caution. On prior testing, see the discussion in allergy test for filler; its usefulness and indication vary and depend on the professional's judgment.
In Harmy
Harmy does not identify skin reactions and does not screen for allergies. The projection uses the frontal photo and is illustrative. Recording allergies and managing reactions stay in the patient record and in the professional's judgment.
Also called: hives, welts, skin allergy.
Frequently asked questions
Is every red welt after a procedure urticaria?
No. Redness and swelling at the injection site are common and are usually a local reaction. Urticaria spreads as welts that move around and itch. When in doubt, the assessment belongs to the professional.