Conditions
Hives: itchy welts, what causes them and when they are an emergency
Hives are raised, red, itchy welts that change shape and come and go within hours. They are usually mild and work well by video. Safety first: if your lips or tongue are swelling, you are struggling to breathe or you feel faint, call 911 now. Otherwise the doctor looks for the cause and, if appropriate, prescribes and we send your prescription to your pharmacy.
Is it an emergency? Call 911.
Is this an emergency?
This is not an emergency service. Call 911 or go to the nearest emergency room if you have:
- Swelling of the lips, tongue, face or throat
- Trouble breathing, wheezing or a tight throat
- A hoarse or whispery voice, or trouble swallowing
- Dizziness, fainting or feeling about to faint
- Nausea or vomiting along with the hives
Help lines
At a glance
Hives
Common symptoms
- Raised, red or skin-colored welts that itch
- Welts with clear edges that grow and merge
- Welts that change shape, disappear and come back within minutes or hours
- Other names
- Urticaria · Welts · Chronic hives
- Treatment
- Antihistamine; other prescription medicines only when the medical evaluation calls for it
- Possible complication
- Anaphylaxis (severe allergic reaction)
On this page(9)
Hives with trouble breathing: call 911
Hives can be part of a severe allergic reaction (anaphylaxis), which is life-threatening. Call 911 right away if hives come with any of these signs. If the person has an epinephrine auto-injector, help them use it while help is on the way. See when to go to the ER.
- Swelling of the lips, tongue, face or throat
- Trouble breathing, wheezing or a tight throat
- A hoarse or whispery voice, or trouble swallowing
- Dizziness, fainting or feeling about to faint
- Nausea or vomiting along with the hives
What are hives?
Hives (urticaria) are red or skin-colored raised welts with clear edges that itch. They can grow, join together, change shape, and disappear and come back within minutes or hours.
Often they are an allergic reaction to foods (such as shellfish or nuts), medicines, insect bites or pollen. They also happen without an allergy: from infections, stress, heat or cold, sweating, exercise or pressure on the skin. In Puerto Rico’s heat, sweat and tight clothing can make them worse. Often no cause is found.
Hives that last more than 6 weeks are called chronic hives. A cause is rarely found, and most cases go away on their own within a year.
How we treat hives by video
You see Dr. Diana Nieves Castro, a Puerto Rico–licensed general practice physician with several years of emergency-department experience, in English or Spanish. Show the welts on camera in good light or send photos through the secure link we send you; because hives come and go, a photo from when they were at their worst helps a lot.
The doctor asks what you ate, what medicines you took, whether something bit you or you’ve been sick, and whether you have ever had face swelling or trouble breathing. From there she evaluates, diagnoses and treats. If appropriate, the doctor prescribes and we send your prescription to your pharmacy.
We see adults and children of all ages; patients under 21 need a parent or legal guardian on camera with ID. You need to be physically in Puerto Rico during the visit; visitors are welcome.
Your doctor
Dr. Diana Nieves Castro, MD
General practice physician
Several years of emergency-department experience.
Founding Executive Director of The Health Initiative.
Your visit in 3 steps
Request a visit online 24/7 — we confirm your time by email or text This is how you see a doctor online with us.
Request your visit.
Book a visit and choose "Doctor visit". You pay by card when you request it.
See the doctor by video.
We send you a secure video link. It works on your phone, tablet or computer.
Get your plan.
If appropriate, the doctor prescribes and we send your prescription to your pharmacy. If needed, you get a lab order.
What the visit costs
Hives are handled in a US$79 doctor visit, the same price for every age, with no membership. You pay by card when you request the visit, and you get a full refund if the visit can’t take place. A doctor’s note after your visit is included. See all prices.
Hives symptoms
What you usually see:
- Raised, red or skin-colored welts that itch
- Welts with clear edges that grow and merge
- Welts that change shape, disappear and come back within minutes or hours
Hives treatment, and when a lab test is ordered
Mild hives often go away on their own. For the itch, avoid hot baths or showers and tight clothing. The doctor may suggest an antihistamine, and chronic hives may need a prescription medicine. If you know what set them off, avoid it.
If hives last more than 6 weeks or keep coming back, the doctor decides whether a lab test would help: we give you a lab order for a lab near you and go over the results with you in a follow-up visit.
If your hives came with face swelling or trouble breathing, even if it has passed, tell the doctor: you may need to carry epinephrine and see an allergy specialist.
Hives, allergies and other rashes
If your problem is sneezing and an itchy nose, see allergy treatment. If your rash isn’t welts that come and go, see skin rash. If your skin itches but you see no welts, see itchy skin.
How we care for you
We evaluate, diagnose and treat; if needed, we give you a lab order for a lab near you.
We see adults and children of all ages. Patients under 21: a parent with patria potestad (parental authority) or a legal guardian is on camera for the whole visit and shows photo ID.
Real-time video visit. We send you a secure video link. It works on your phone, tablet or computer.
If appropriate, the doctor prescribes and we send your prescription to your pharmacy. We do not prescribe controlled substances.
You must be physically in Puerto Rico during the visit (visitors, tourists and cruise passengers are welcome).
In an emergency, call 911.
Frequently asked questions
Can hives be treated by video?
How long do hives last?
What causes hives?
When are hives an emergency?
About this page
Author: The Health Initiative
Medical care provided by Dr. Diana Nieves Castro, MD (PR license 24027)
Disclosure: Founding Executive Director of The Health Initiative
Published: 2026-10-02 · Updated: 2026-10-02
Sources (2)
- Hives (MedlinePlus, NIH) (opens in a new tab) (accessed 2026-10-02)
- Anaphylaxis (MedlinePlus, NIH) (opens in a new tab) (accessed 2026-10-02)