How Is Hives (Urticaria) Diagnosed?

Hives are normally diagnosed by performing a detailed physical examination of the idiosyncratic reddish rash. If a patient is suffering from long-term hives, several tests may be done to establish the underlying cause.

Acute Hives Diagnosis

A general medical practitioner can simply diagnose mild urticaria by keenly examining the skin rashes. He or she will try finding out the exact causes since these factors could help the individual to overcome recurrent effects. Typically, the physician will ask you the following questions:

• when the rash began
• where the episode occurred
• what you had consumed just before the symptoms began and your regular dietary habits
• whether you live or work in an environment where potential triggers could be prominent, like chemicals, animals, and latex gloves.
• your medical history
• if any insect stung or bit you just before the signs or symptoms started
• whether you’ve been taking alternative treatments including herbal supplements
• if you have lately traveled abroad, and if so, which country in particular
• if your family has an existent history of hives or urticaria

Acute Urticaria

Acute urticaria often becomes visible after a short period of coming in touch with an allergen.  Wheat, peanuts, shellfish, and eggs are common foods that are known to trigger hives. This classification of urticaria lasts for about one to two days and usually resolves on its own without treatment. Others may experience sudden urticaria that would last for more than a month.

Regardless of age, anyone can be affected by this skin condition. Studies show that one in six people may develop urticaria for at least once in their lifetime, while some may be challenged by a recurring urticaria.   

Symptoms of Acute Urticaria

Although most individuals suffering from acute urticaria are generally well, management of the rashes and their corresponding itch can be very irritating. Angioedema is almost similar to urticaria. However, the swelling in angioedema originates under the person’s skin rather than on the surface like in urticaria. Usually, the lips, eyelids, and genitalia are mostly affected by angioedema swelling.

There are also manifestations of swelling seen in the throat and tongue of an affected individual. For this reason, if there is severe swelling in the tongue and throat, it can cause a person to have breathing difficulties. The areas affected by angioedema may heal and shrink after three days.

Urticarial vasculitis is a type of vasculitis, which develops in the skin as hives and may appear as red patches or weals. Weals can be very painful and they usually last for more than one day. They also tend to leave a reddish mark on your skin when it is healed.

Reaction to Medications

Certain medications like sulfonamide, clotrimazole, glimepiride, and anticonvulsants can cause unusual reactions. For many acute hives cases, the exact cause cannot be identified. If your primary care practitioner thinks that the symptoms could be as a result of allergic reactions, you might have to visit an allergic clinic.

Long-term (chronic) Hives

If your symptoms last for more than two months, it is most unlikely that they are allergy-related, so instant allergy tests are not usually recommended. Nevertheless, your doctor should inquire about any other factors that contribute to your symptoms’ severity.

Such factors include:

• Any medications you are taking
• Your stress, anxiety, or depression levels
• Your caffeine or alcohol consumption details

To determine if any other underlying causes of your illness are prevalent, you could be put under numerous tests including:

• A stool sample aimed at identifying intestinal parasites
• Full blood count tests - FBCs are carried out to identify anemia
• Thyroid function tests - such tests are done to check for hyperthyroidism or hypothyroidism disorders
• Erythrocyte sedimentation rate examinations - can aid in identifying problems relating to one’s immune system
• Tests to establish your blood’s antibody levels
• Liver function tests – tests that are used to check for any liver malfunctions

Other Medical Causes

Urticaria is also linked to infectious diseases in the form of bacterial, viral, parasitic, and fungal infections. This type of skin condition is also seen among individuals suffering from lymphoma. That is why proper consultation and screening should be done to know the history of each patient with urticaria.

Urticaria can recur with the following medical disorders:

• Hepatitis C-related cryoglobulinemias
• Chronic lymphocytic leukemia (CLL) 
• Immune complex-induced inflammation
• Serum sickness
• Rheumatologic diseases such as systemic lupus erythematosus (SLE) and arthritis
• Thyroid diseases (hyperthyroidism and hypothyroidism) 
• Polymorphic eruption of pregnancy (PEP)

Allergy Testing

Skin prick tests are normally performed to confirm the presence of an allergy. The skin that is beneath the forearm or at the back is thoroughly cleaned and pricked using small amounts of the presumed allergen. If an individual is allergic, the skin will instantly react and becomes itchy, swollen, and reddish. Since minimal amounts of the allergen are used, the test does not really trigger more adverse allergic reactions.

Another alternative test is the advanced patch test. This test entails placement of little amounts of the presumed allergen on metal discs, and then tapping it to the patient’s skin and left for two days to determine if an allergic reaction takes place.

If you think that your symptoms are related to hives, consult your doctor for a confident diagnosis. Do not prescribe any supplements for yourself. Treating the right disease with the proper treatment is very important to your health.

Diagnosis

The clinical diagnosis of urticaria is usually based on the patient’s history as well as the time when the rash appeared. Sometimes, other skin conditions such as eczema can be easily confused as hives if the patient’s history is unclear.

Differential diagnosis

• Atopic dermatitis – is also commonly referred to as eczema. This type of skin condition affects all ages but is more prevalent among children. Eczema is characterized by an inflamed and itchy skin with frequent flare-ups. Due to itching and irritation, rough skin may develop blisters that bleed when scratched.

• Erysipelas – is a bacterial infection of the skin. It usually starts with a rash characterized by large and inflamed skin patches that can be found particularly on the face and legs. This type of rash is usually accompanied by fever due to bacterial infection.

• Chronic pruritus  (itchy skin) -  can be due to a host of factors from allergies, drug reactions, dry skin, pregnancy, dermatitis, psoriasis, and other skin conditions.

• Pemphigoid – is caused by an autoimmune disorder more commonly seen among the elderly people. This skin condition happens when there is an immune system malfunction. Symptoms include rashes and blisters on an individual’s arms, legs, and abdomen. In some cases, pemphigoid is seen among expectant mothers.

• Polymorphic eruption of pregnancy (PEP)-  is also called as plaques of pregnancy, wherein an itchy rash starts to form along the stretch marks of a pregnant woman during her third trimester. The rash usually goes away after delivery.

• Urticaria pigmentosa – usually develops extremely itchy and dark skin patches. When these areas are frequently scratched or rubbed, hives may develop.

• Duhring's disease - is also known as dermatitis herpetiformis. Its name suggests a similar description of a skin inflammation caused by the herpes virus. Skin blisters and itchy papules are the main manifestations of this disease.

• Erythema multiforme – is a type of a hypersensitivity reaction due to other underlying conditions, particularly infections caused by the herpes simplex virus. The rash may develop into blisters and scabs on both sides of the body. It can easily be identified as it forms a "bulls-eye" patch on the skin.