What Is a Physical Allergy?
There are various substances that can trigger allergic reaction in people. One of the allergy types that experts tend to distinguish apart from others is a physical allergy. A physical allergy is overreaction of the immune system caused by exposure to a physical stimulus.
Physical stimuli that may potentially trigger an allergic reaction include: cold, sunlight, physical pressure, heat or any sweat-inducing activities, vibration, as well as mild injuries.
In some people, the physical stimuli lead to the development of allergy symptoms, while in others, they make existing allergies worse.
Sensitivity to cold may be associated with abnormal proteins like cryoglobulins or cryofibrinogen in the blood of an affected person. In some cases, these proteins may indicate a serious underlying disease, including cancer, chronic infection, or a connective tissue disorder.
What Is the Cause of Physical Allergies?
Experts still don’t understand the exact causes of a physical allergy, but there are some theories about it. According to one of them, an allergic reaction occurs because of changes in a protein in the skin caused by the physical stimulus. The immune system overreacts to the protein, as if it was a foreign substance and releases histamine and antibodies to protect the body. An example could a sunlight sensitivity, also called photosensitivity. Ultraviolet light alters the proteins in the skin leading to an allergic reaction. Some people can develop photosensitivity after using drugs (e.g. antibiotics), cosmetics like creams, lotions, and oils, or other products.
What Are the Symptoms of Physical Allergies?
In most cases, physical allergic reactions cause symptoms like itching, hives, and angioedema (swelling of tissues under the skin). The symptoms occur soon after the exposure to the physical stimulus.
If you have a heat sensitivity, exposure to heat or engagement in any sweat-inducing activity may cause you develop cholinergic urticaria. This condition causes small hives surrounded by a ring of redness that are extremely itchy.
In people with cold sensitivity, exposure to cold may trigger hives, nasal congestion, or angioedema. In severe, but rare cases, it may lead to anaphylaxis.
How Is a Physical Allergy Diagnosed?
If you develop abnormal symptoms after exposure to the physical stimuli, you should arrange a visit to an allergist. Based on your symptoms and the situation that has lead to these symptoms, the doctor will make a diagnosis.
A sensitivity to cold can be diagnosed using an ice cube placed on the skin for about 4 minutes. If a hive occurs at the affected site of the skin, a person is allergic.
Your doctor may also recommend that you stop use cosmetics and skincare products for a while to see whether your symptoms are caused by substances contained in these products.
How Do You Treat Physical Allergies?
The best way to prevent an allergic reaction to a physical stimulus is to avoid the allergen. Thus, if you are allergic to sunlight, you may want to avoid direct exposure to the sun as much as you can and use a sunscreen whenever you go outside.
Various symptoms including itching can be reduced by antihistamines. To treat hives caused by cold, you can use cyproheptadine, while for hives induced by heat or stress, you can try hydroxyzine.