Irritation of the skin can be caused by many different factors. Allergens, heat, cold, medications, immune system disorders, and infections can all trigger problems with the skin. While our physician treats many skin conditions, our focus is concentrated on immunological triggers. The main skin conditions we treat are dermatitis (also known as eczema), urticaria (also known as hives), and angioedema (swelling of the deep layers of the skin).
Dermatitis is an umbrella term for irritation or inflammation of the skin. The term “dermatitis” is often used interchangeably with “eczema”. When the irritation or inflammation is caused by direct contact with an allergen, it is called allergic contact dermatitis. Examples of allergic contact dermatitis include poison ivy, poison oak, sensitivity to metals, or sensitivity to chemicals. People can develop this form of dermatitis by direct contact with allergenic substances, or by touching a secondary item. For example, if a pet has run through a patch of poison ivy, a person can develop an allergic response by petting that animal. It is important to be cautious of contact with unknown plants and to become familiar with what potentially problematic plants to avoid.
Similarly, a person with a nickel sensitivity can develop allergic contact dermatitis while wearing jewelry with even a small amount of nickel. Many chemicals, metals, and household substances can cause irritation, inflammation, and itching of the skin. There are countless substances that can act as an irritant to sensitive skin, so it is important to identify your triggers and avoid the known irritants. Our board-certified allergist can assist you with identification of such irritants and develop a plan to avoid contact with know triggers.
Atopic Dermatitis (Eczema)
Atopic dermatitis, or eczema, is an allergic disease that tends to have a hereditary component and seems to run in families whose members also have asthma. Itching will usually precede the development of a rash. When a rash does develop, it may appear as patches of dry, hardened skin. The most common areas affected in adults include the hands, neck, face, and legs. In children, presentation usually involves creases of the knees and elbows. There is a strong link between the development of eczema and food allergies, especially in young children. The food groups most commonly implicated include wheat, peanuts, eggs, milk, soy, fish, and seafood. Latex and peanut allergy are also more common in patient’s with atopic dermatitis. Urticaria and acute anaphylaxis to foods have been found to be more prevalent in patients with atopic dermatitis.
Urticaria, or hives, is a condition that affects approximately 20% of people at some point in their lives. Hives can be either an acute or chronic condition. Symptoms of hives include:
Swelling or raised red or white bumps or welts that:
- Can cover large areas and migrate from one spot to another
- Range in size
- Appear anywhere on the body
Acute hives are hives that last less than 6 weeks. Acute hives are the form that develop with ingestion af allergenic foods or contact with irritant substances. The most common causes of acute hives are peanuts, tree nuts, shellfish, eggs, food additives, medications, aspirin, sulfa antibiotics, penicillin, blood transfusions, insect stings, and infections. Examples of infections that are commonly linked to the development of acute episodes of hives are the common cold, urinary tract infections, infectious mononucleosis, strep throat, and many viral infections. In most cases of acute hives, the symptoms will resolve once the trigger substance is removed or avoided.
In contrast, chronic hives last or reoccur for more than 6 weeks. Chronic hives need to be evaluated by an allergist to investigate and identify the root cause. In some case, the cause of chronic hives cannot be identified even after testing and detailed evaluation. When the cause cannot be determined, the condition is called ideopathic urticaria. Approximately 50% of cases of idiopathic urticaria are caused by immune system disorders. The remaining cases are caused by thyroid disease, hormonal disorders, rarely cancer, and other physical causes. Examples of physical causes that can trigger reoccurring episodes of hives are:
- Rubbing or scratching (dermographism). This form of hives is the most common cause of chronic hives. The lesions typically appear within a few minutes in the area being scratched or rubbed. This form of hives often disappears with a half hour or less.
- Constant pressure (pressure urticaria). Hives can also appear as red swelling caused by constrictive clothing such as belts and socks.
- Change in temperature. Hives may be caused by heat or cold. Hives called cold urticaria are caused by exposure to low temperature followed by re-warming. This can be severe and life threatening if there is a general body cooling, for example after a plunge into a swimming pool. Hives called cholinergic urticaria are due to an increase in body temperature with sweating, exercise, hot showers, and/or anxiety.
- Sun exposure (solar urticaria). Hives may occur within a few minutes after exposure to the sun.
It is important to note that while hives, acute or chronic, may be unpleasant, they are by no means contagious.
Angioedema is swelling in the deep layers of the skin, often seen with urticaria (hives). Angioedema most often occurs in soft tissues such as the eyelids, mouth or genitals. Angioedema also has acute and chronic forms. Acute cases last hours to days and are often triggered by medications or foods. Chronic cases reoccur over a long period of time and often have no identifiable cause. Another form of this disease is hereditary angiodema (HAE), which is a rare, but serious, genetic condition involving swelling in various body parts including the hands, feet, face, intestinal wall and airways.