URTICARIA - SKIN ALLERGY PART TWO

By DLdoubleE - Own work, Public Domain, Wikimedia

Atopic dermatitis was our topic of discussion. So today we'll get to know about a very common disease URTICARIA.

WHAT IS URTICARIA?

The word Urticaria was coined from the Latin word “urtica” which means “to burn”. It is characterized by red itchy bumps on the surface of the skin which leads to inflammation of the skin. They are sometimes referred to as welts or wheels or hives and range in different sizes. They can move from being a small patch to the size of the palm. Though they can appear anywhere in the body even on the tongue and ear, they are commonly seen around the neck, buttocks, and chests.

Urticaria usually presents with mild Angioedema whereby the top layers of the skin (dermis and epidermis) are inflamed making the part of the skin affected smooth and raised above the surrounding area.

They are sometimes referred to as rashes but the sole difference between them is that while hives are very itchy, change in size and shape and appear as plaques; Rash is like lesions. A severe rash can lead to urticaria.

INCIDENCE

Urticaria is very common. It affects about 20% of the population and 1 in every 5 people have suffered from urticaria at some point in their lives. It can affect adults (30-60 years) even though it is commonly seen in children and people who have a history of allergies. No gender is more prone to urticaria, It affects males and females equally.

CAUSES OF URTICARIA

They are mostly caused by the body's response to allergies. For better understanding, Read more on allergy and allergen from my previous post.Atopic Dermatitis

Though allergies are the most common cause of urticaria, There are some other factors that can lead to urticaria.

Blood Transfusion

Urticaria is one of the most common symptom of transfusion reaction.

Transfusion reactions are effects associated with blood transfusion either from the transfusion of a whole blood or one component of it.

Transfusion reaction mostly occurs when the body identifies a particular content of the blood as foreign (antigen) and produces antibodies (IgE antibody) to get rid of it. This reaction between the antigen and antibody can lead to urticaria.

Chemicals

Substances like additives and preservatives can trigger inflammatory responses when in contact with the skin.

Medication

According to research, 9% of Urticaria are caused the side effects of so many drugs. Such as; penicillin, Non-steroidal anti-inflammatory drugs (aspirin), and Codeine.

Some other causes of urticaria include;

Physical factors such as pressures, cold, heat.

Insect bites.

Stress.

By James Heilman, MD - Own work, CC BY-SA 3.0, Wikimedia

TYPES OF URTICARIA

There are several types of urticaria which includes;

ACUTE URTICARIA

They are usually caused by medications, food (especially fresh foods), infections. They are self-limiting and don't last more than 6 weeks.

CHRONIC URTICARIA

This type of urticaria is mostly caused by an underlying disease such as thyroid disease, hepatitis, or cancer. It is not self-limiting and can last for more than 6 weeks. Chronic urticaria can affect organs such as the lungs, muscles, and gastrointestinal tract. Some presentable symptoms of chronic urticaria includes;

• Shortness of breath (difficulty breathing)
• Muscle soreness (The pain that occurs after trying an unfamiliar exercise)
• Vomiting and diarrhea.

PATHOPHYSIOLOGY OF URTICARIA.

In the presence of an allergen or any substance that stimulates the skin, the body releases antibodies (IgE antibodies) These antibodies bind to the antigen and identify it as a foreign body. The reaction between the antibody and antigen stimulates the release of histamine and other inflammatory mediators. Histamine act by increasing vasodilation (widening of blood vessels) which causes the rush of blood to the skin leading to the redness of the skin and inflammation.

SIGNS AND SYMPTOMS OF URTICARIA.

Itching

It is most times the first sign of urticaria. It occurs due to the release of histamine.

Wheels

It is characterised by small reddish bumps, that occur in different sizes. In severe cases, they cluster together to form patches.

Swelling

It is occurs due to vasodilation triggered by histamine (inflammatory mediator).

These symptoms in acute urticaria disappear after one hour, they are usually self limiting.

There is a high risk of research reoccurence.

DIAGNOSTIC INVESTIGATION

Diagnosis depends on the type of urticaria.

ACUTE URTICARIA

It can be diagnosed by;

1. physically examining the skin
2. Identifying the triggers
   Patients can be asked questions like:

• When and where did you first notice the episode?
• Has there been an insect bite of recently?
• Are there potential triggers such as latex gloves, chemicals, or animals - - where you live or at your place of work?
• Are you on any medications or herbal supplements?
• Do you have a family history of allergy?

Skin Patch test can also be done to identify the particular allergy.

CHRONIC URTICARIA

If urticaria continues after 6 weeks, there is a high chance that its trigger is not external so a skin patch test might not be necessary. However, diagnostic investigations can be done to identify the underlying disease.

• Blood test to check for anemia
• Stool sample to rule out parasitic infection.
• Erythrocyte sedimentation rate (ESR) test, to identify immune system problems.
• Thyroid function test to identify hyperthyroidism (overactive thyroid) or hypothyroidism (underactive thyroid)
• Liver function tests to identify liver problems

TREATMENT

Antihistamines
They are the first treatment for urticaria. They work by blocking the action of histamine thereby preventing inflammation. Example of antihistamine: loratadine, Cetirizine

Other medications include;
Anti-inflammatory drugs
Medications such as: prednisone can help reduce swelling, redness and itching. These are generally for short-term control of severe urticaria because they can cause serious side effects if taken for a long time.

Immune-suppressing drugs
Immune-suppressing drugs can help reduce inflammation by slowing down the immune system.

References

National Library of Medicine

Medscape

Medlineplus

Drugs.com

I hope this was beneficial to you.
Do well to drop your thoughts or questions in the comment section.
Thank you so much.