Skin Allergy

Overview about Allergy

Bumps, itching, redness and other skin conditions are very common, and their cause may not be easily identifiable. Rashes can be caused by many things, including plants (poison ivy, for example), allergic reactions to a medication or a food, or an illness (measles or chickenpox, for example). Eczema and hives, both of which are related to allergies, are two of the most common skin rashes.

Atopic dermatitis

Atopic dermatitis is the most common form of eczema, affecting between 10 and 20 percent of children and 1 to 3 percent of adults. A common symptom of atopic dermatitis is dry, red, irritated and itchy skin. Sometimes, especially when infected, the skin may have small, fluid-filled bumps that ooze a clear or yellowish liquid. People with atopic dermatitis often have a family history of allergies.

Hives

Hives (urticaria) are red bumps or welts that appear on the body. The condition is called acute urticaria if it lasts for no more than six weeks, and chronic urticaria if it persists beyond six weeks. Acute urticaria is most commonly caused by exposure to an allergen or by an infection. The cause of chronic urticaria is largely unknown.

Contact dermatitis

Contact dermatitis is a reaction that appears when the skin comes in contact with an irritant or an allergen. Symptoms can include a rash, blisters, itching and burning.

Soaps, laundry detergents, fabric softeners, shampoos — or even excessive exposure to water — can all cause contact dermatitis. Other items that can cause a reaction are metals (such as nickel, a component of stainless steel and other alloys used to make costume jewelry), adhesives, nail polish, topical medications, plants and latex gloves.

Sometimes an allergen won’t cause a skin reaction unless the skin is also exposed to sunlight. This condition is called photoallergic contact dermatitis. It can occur with products such as shaving lotion, sunscreen and some perfumes.

SKIN ALLERGY SYMPTOMS & DIAGNOSIS

Itching, redness and swelling are common to most skin allergies. Yet there are some differences that help in the diagnosis of specific conditions.

Atopic Dermatitis (Eczema)
Symptoms
Itchy, red or dry skin. It may “weep” or leak fluid that crusts over when scratched, which means that it is also infected.

In infants, eczema often appears on the face. Children are prone to have the rash at the bends of the elbow joint, wrists, behind the knees and behind the ears. Adolescents and young adults typically have the rash in the same locations as children, as well as on the hands and feet.

Patients with the faulty filaggrin gene often have hand eczema with excessive little lines on the skin of their palms.

Diagnosis
In many children, the exact cause of the eczema is not clear and treatment depends on regular use of moisturizer and topical medicines to dampen down the inflammation. One such treatment is topical steroids. In children where the skin is oozing, crusting and painful, an infection that needs treatment with antibiotics may be the primary trigger.

Infants and young children with more severe eczema should be evaluated for food allergy. It’s important to see an allergist / immunologist for diagnosis and management. It is often needed to receive input from a dietitian as well.

Food allergies causing eczema are much less common in older children and adults. If you are suspected of having eczema that is caused by a food allergy, a confirmed diagnosis requires avoiding the trigger food for about four weeks with the help of a dietitian before doing a food challenge under your doctor’s supervision to confirm that the food was actually causing the flare.
Urticaria (Hives) and Angioedema
Symptoms
Urticaria is itchy, red and white raised bumps or welts that range in size and can appear anywhere on the body. Angioedema often appears on the face around the eyes, cheeks or lips. This deeper layer of swelling can also occur on hands, feet, genitals, or inside the bowels or throat. In acute urticaria, the welts disappear within minutes to a few weeks. Chronic hives last for months or even years.
Diagnosis
In the majority of chronic cases, the exact cause cannot be determined. Routine testing such as general blood counts or screens are not cost-effective, nor do these tests make a difference in treatment strategies to relieve the symptoms. There are certain instances when allergy testing is helpful, especially when eating a particular food or coming in contact with a particular substance triggers symptoms of acute hives.

SKIN ALLERGY TREATMENT & MANAGEMENT

Atopic Dermatitis (Eczema)
Eczema is sometimes described as an “itch which rashes.” The rash is caused by scratching, so the more the patient scratches the more severe the rash will be. This is why it’s important to avoid scratching.

The most effective way to treat eczema is to use moisturizers and topical ointments that reduce the inflammation e.g. topical steroids or calcineurin inhibitors. The itch is not relieved by antihistamines although these are sometimes used at night to help people with eczema sleep.

Antibiotics may be prescribed if a skin bacterial infection is suspected as a trigger for your eczema flare-up. Symptoms include crusting, oozing and pain. Oral steroids should be avoided, as although they are effective the eczema usually returns when the medicine is stopped. Oral steroids can also cause serious side-effects if taken for long periods of time.

Sometimes cotton undergarments and body suits help protect the skin from irritants and from scratching. Avoid using soap products that contain sodium laurel sulfate and any triggers that cause a reaction. Your allergist will be able to help determine whether there is a trigger that can be avoided.

These skin allergy treatment and management strategies can relieve social challenges as well. People with eczema, especially children, are sometimes ignored or singled out by others who believe the rash is contagious.

Urticaria (Hives) and Angiodema
If the cause of your hives can be identified, you can manage the condition by avoiding that trigger. Treating hives or angioedema is often successful with oral antihistamines that control the itch and recurrence of the rash.

If the rash is not controlled with a standard dose of the antihistamine, your doctor may suggest increasing the dose for better control of your symptoms. If antihistamines do not control the rash, or if it leaves bruises, then it is important that your doctor rules out other causes which may need alternative therapies.

If you are on certain blood pressure medicines (ACE inhibitors) and develop angioedema, it is important to consult your doctor. Changing to another blood pressure medicine may help the angioedema go away.