Urticaria is commonly known as hives. It is usually diagnosed based on the appearance, history, and associated factors and confirmed upon examination by a physician. Taking a photo of the affected skin during the attack is helpful to guide the physician as to whether this is urticaria or not.
Hives are usually reddish raised areas on the skin which are itchy. On darker skin, the redness may not be very visible.
Hives often disappear, and new hives may appear in other areas; however, an individual spot does not last more than 24 hours, and the skin appears normal upon resolution. Changes in the skin like bruising, blood-like spots, or brown discoloration are usually not seen in urticaria.
Hives on the skin may sometimes occur along with swelling and itching of loose skin tissue like the lips, eyelids, tongue, or the tissues inside the mouth; this is called angioedema. In some conditions, angioedema can occur alone, without associated urticaria.
Your doctor will ask you questions regarding any other intercurrent illness, medication use, or exposures that may trigger urticaria and about other symptoms that indicate systemic involvement like fever, joint pain, weight loss, or malaise.
Hives may come and go for days at a time. Hives that last more than six weeks are referred to as “chronic urticaria.”
Three key elements are essential for the diagnostic approach to urticaria. The first element is to confirm the correct diagnosis (acute versus chronic, exclude other differential diagnoses and reach the correct classification of either Chronic Spontaneous Urticaria (CSU) (previously called idiopathic) or Chronic Induced Urticaria (CIndU). The second is to determine the culprit or triggers. The third is to assess the burden of urticaria on the patient (urticaria activity scoring, degree of urticaria control, and impact on life).
Your doctor will also ask you about:
- smoking habits
- type of work
- symptom occurrence in relation to weekends, holidays, and foreign travel
- surgical implantations
- relationship to the menstrual cycle
- response to therapy
He may ask about your family members who may have similar symptoms or other allergies. Additionally, these symptoms will be revisited while on a different regimen of treatments until disease control is achieved.
Clinical Examination and Identifying the Cause
Urticaria is not a disease in itself; it is only a symptom. Urticaria can be associated with various conditions and triggers; see the section on “triggers” below
Depending on the pattern of presentation and history, your doctor may be able to identify the cause.
Usually, no specific cause or trigger despite examination and testing is identified in most patients. In these cases, “idiopathic” (a medical term indicating no real cause) is used.
Various things can trigger urticaria, including infections, certain medications, allergy to food or food additives, insect bites or certain plants, and physical factors.
Some patients have urticaria triggered by physical factors such as pressure, scratching, heat, cold, vibration, water, and sunlight.
- Viral, bacterial, and parasitic infections are among the causes of hives
- Food allergies can cause hives. In addition, a patient with a food allergy may also present with angioedema, vomiting, diarrhea, dizziness, and collapse if the reaction is very severe (in this case, the skin hives are part of another disease called anaphylaxis).
- Food additives such as preservatives, coloring agents, etc.
- Allergy to a new medicine
- Allergy to insect stings
- Allergy to latex- which is contained in rubber gloves, balloons, condoms, etc.
- Tobacco use is known to induce urticaria
- In female patients, the state resulted in hormonal changes like pregnancy and menstrual cycles that may induce urticaria.
- Stress is a very well-known immunologically provoking factor.
Your doctor may do a general and comprehensive bedside examination. Usually, your clinical examination is expected to be normal. Your doctor may perform specific provocation testing if he suspects CIndU (ice cube, heat stimulus, photo-light test, or stroking the skin with a blunt, firm object).
Usually, testing is not required to diagnose spontaneous urticaria that is acute or lasting less than 6 weeks (hives occurring with no identified trigger). If it lasts longer than six weeks, your doctor may consider doing some tests.
Some blood tests may be requested in chronic hives to check if your hives are a part of any other disease.
If your hives are clearly triggered by food or medicines, your doctor may recommend allergy testing by skin prick testing or blood tests.
In rare cases a skin biopsy (taking a small sample of skin) may be required, especially if there are some unusual features or you do not respond to the usual treatment.
It is always helpful to have photos of your hives since they change over the course of hours. It is particularly important to check your skin for any persistence, sequelae, or pigmentations after 24 hours of lesions and to take photos in order to help reach a proper diagnosis and exclude other differentials.
If no cause is identified, it may be helpful to keep a diary of symptoms and note down all the associated events; this may help identify the trigger.