Hives (Urticaria) in Ho Chi Minh City: Acute, Chronic and Warning Signs
Urticaria is a relatively common allergic skin reaction that causes itching and discomfort.
Medically reviewed by Dr Quynh Trang, Dermatologist (HCMC)
Don’t underestimate urticaria. It can be acute or chronic, and in some cases, may signal a medical emergency. Wedo dermatologists can help identify the type of urticaria and determine the appropriate course of action.
How it works
Signs of Urticaria
Urticaria (hives) appears as raised patches of skin that are red or pale pink, with well-defined borders and intense itching. They can vary in shape and size, appearing as round, oval, or ring-shaped lesions. Some may be only a few millimeters in size, similar to mosquito bites, while others may merge into larger patches the size of a palm. Urticaria usually resolves spontaneously within 24 hours. The mechanism is as follows: mast cells in the dermis contain inflammatory mediators, mainly histamine. When activated, they release histamine into the surrounding tissue. Local capillaries dilate and leak fluid into the tissue, causing the raised swelling, while sensory nerve endings are stimulated, resulting in intense itching. The fluid is rapidly reabsorbed by the body, so the wheals flatten and disappear within 24 hours without leaving marks. This is also useful for distinguishing urticaria from dermatitis. Dermatitis causes red, dry patches that may ooze, persist in the same area for several days, and may leave hyperpigmentation or cause the skin to become thickened.
Acute or Chronic Urticaria?
In general, acute and chronic urticaria are distinguished by the 6-week duration. Acute urticaria does not necessarily progress to chronic urticaria simply because it is not treated properly. Acute urticaria lasts less than 6 weeks and accounts for most cases. It is often associated with a trigger such as certain foods, medications, infections, or insect bites, and usually resolves when the trigger is removed or the underlying condition improves. Chronic urticaria persists for 6 weeks or longer, with symptoms occurring on most days of the week. It can be particularly burdensome, not necessarily because the lesions are more severe, but because the symptoms may persist without a predictable endpoint. Chronic urticaria may be more difficult to control and requires appropriate evaluation and treatment. Persistent scratching and inflammation may also lead to secondary skin changes such as eczematization and post-inflammatory hyperpigmentation.
Common Triggers of Urticaria
There are many possible triggers for acute urticaria: - Food and beverages: Seafood, peanuts and tree nuts, eggs, milk, and certain food additives. A typical clue is that the reaction occurs within a few hours after eating and recurs in the same pattern. If you regularly consume the same food without developing hives, it is less likely to be the trigger. - Medications: Certain medications can cause urticaria in susceptible individuals. Rather than trying to identify the culprit yourself, bring a complete list of everything you are taking to your appointment, including supplements, vitamins, and traditional medicines. Do not stop medications prescribed for underlying conditions without consulting your doctor. - Infections: A cold, sore throat, or viral infection may occur shortly before or alongside an episode of acute urticaria. The two may be difficult to connect because the respiratory symptoms can resolve before the hives appear. - Heat and sweating: Sun exposure, exercise, spicy foods, and hot showers can trigger cholinergic urticaria, which typically presents as very small, intensely itchy or prickling papules. - Pressure and friction: Backpack straps, bra straps, waistbands, or even areas that have been scratched can trigger hives. If lightly scratching the skin causes a raised line to appear along the scratch, this is known as dermographism. - Sudden cold exposure: For example, moving from direct sunlight into an air-conditioned room or drinking iced beverages. - Weather changes: Seasonal transitions, fluctuating weather, and the year-round high humidity in Ho Chi Minh City may trigger flare-ups in people who are prone to urticaria. For chronic urticaria, identifying a specific trigger is often much more difficult.
Cases of Urticaria Requiring Immediate Emergency Care
If urticaria occurs with any of the following symptoms, seek emergency medical care immediately: - Difficulty breathing, wheezing, stridor, or chest tightness - Swelling of the lips, tongue, or area around the eyes, or a sensation of throat swelling or tightness - Difficulty swallowing, hoarseness, or changes in the voice - Dizziness, lightheadedness, sweating, or fainting; vomiting accompanied by severe abdominal pain The following situations are not necessarily emergencies, but you should seek medical evaluation promptly: urticaria lasting 6 weeks or longer or recurring frequently; an individual lesion that remains in the same location for more than 24 hours, is more painful or burning than itchy, or leaves bruising or hyperpigmentation after it resolves; urticaria accompanied by fever, joint pain, unexplained weight loss, or persistent fatigue; itching that disrupts sleep or affects daily activities; pregnancy; use of multiple medications or the presence of an underlying medical condition; or symptoms that do not improve after self-medication.
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Treatments & pricing
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5 steps, clinically led
Step 1: History along a timeline
Your dermatologist asks in detail: when it started, how long an individual welt lasts before fading, whether there has ever been swelling of the lips or around the eyes, and everything you are currently taking, supplements included.
Step 2: Examination and classification
Your dermatologist examines the skin directly and under magnification, classifies the episode as acute or chronic against the six-week mark, and rules out the situations that need further assessment before treatment begins.
Step 3: Plan discussion and a specific quote
Your dermatologist explains what you have, what a realistic goal looks like for it, which steps are involved and over what period — then quotes the cost specifically, before you decide anything.
Step 4: Treatment
Where it is needed, medication is prescribed for you individually, alongside guidance on easing the itch at home and on limiting whichever triggers have been identified.
Step 5: Review and a maintenance plan
Your dermatologist assesses the response, adjusts or stops medication at the right point, goes through your diary with you, and sets a plan for the settled periods between flares.
Make results last
Easing the itch at home, safely, while a flare is running
Nothing below replaces your dermatologist’s plan. These measures do one job: make you more comfortable while an episode is running its course.
- Apply a cool compress or a cool damp cloth; bathe in cool to comfortably warm water and never hot — heat makes hives worse almost immediately.
- Use a gentle, fragrance-free cleanser and avoid harsh bar soaps.
- Wear loose cotton clothing, and take off belts, straps and anything else pressing on the skin.
- Keep your nails short and cool the skin instead of scratching — scratching typically raises fresh wheals along the line you just scratched.
- During an active flare, go easy on strong sun, hard exercise, alcohol and spicy food.
- Keep the bedroom cool at night, since that is when the itch is usually at its worst.
Urticaria Diary: How to Help Your Doctor Identify Triggers
You can keep an urticaria diary to help your doctor identify potential triggers. Include:
- The time when the hives appear and disappear
- Food, beverages, and medications taken within the previous 6 hours
- Activities such as sun exposure, exercise, hot showers, or wearing tight clothing
- The weather conditions that day
- Itching severity on a scale of 1–10
Remember to take photos of the hives while they are still present to help your doctor assess the appearance of the lesions.
Still have questions?
Are hives contagious?
How long do hives last?
Are hives dangerous?
Should I just take an over-the-counter allergy medication for hives?
How are hives different from eczema or dermatitis?
Why do I keep getting hives in Vietnam's climate?
Do I need a referral to see a dermatologist in Ho Chi Minh City?
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