Chemical Exposure: Allergic vs Non-Allergic Reactions

Two different problems can cause a person's response to chemicals. The first is a chemical reaction or sensitivity, and the second is a chemical allergy.

Non-allergic Reactions (sensitivities) to Chemicals

Chemical sensitivities are not always allergies: These are not caused by the body's IgE or histaminic response, the way allergic reactions are. That is, most people can tolerate mild exposure to certain chemicals, but for unknown reasons, others have very pronounced reactions to the same amount of that particular substance. Researchers have not fully determined why some people have allergic-like reactions to chemicals while others do not. Some suggest that such non-histaminic reactions may have a psychological origin, however, it is clearly not the cause in all cases. Symptoms in people who have these sensitivities include one or more of the following:

• Tachycardia, heart rate

• Sweating

• Shortness of breath, asthma symptoms

• Lightheadedness, confusion, memory problems, fatigue, headaches

• Warmth and redness of the face and neck (flushing).

• Chest pain

• Rashes 

• Myalgias (muscle aching), joint pain

Hazardous Exposure at Work

Johns Hopkins cites several substances that commonly set off these non-allergic reactions:

• Carpet and furniture

• Plastics

• Perfumes and other scented products

• Paint

• Cigarette smoke

• Smoke from wood-burning stoves

• Inhaled ozone and nitrogen dioxide, and sulfur dioxide

• Dust storms, forest fires, and volcanic ash

• Vehicle exhaust, petroleum refining, and fossil fuel combustion

• Cleaning fluids 

• Pesticides and herbicides

• Airborne chemicals, like carbon monoxide

Suppose you have a significant reaction that includes one or more of the above symptoms. In that case, it is best to remove yourself from the precipitant and follow up with a medical provider. They can investigate and treat your symptoms accordingly. Because it is not an allergic (IgE) reaction, antihistamines do not typically help.

Allergic Reactions to Chemicals

Chemical allergies occur when exposure to a substance triggers an IgE response. These allergic reactions often stem from an altered immune system. Many people have more than one allergy. Skin/contact allergies are caused by chemicals in a substance that touches the skin. Medication allergies are caused by a chemical in the medicine that is an allergen. Other chemical allergies may be inhaled allergies, such as perfumes, chemical fumes, dust, or other gases.

If you have some allergy symptoms but are unsure what kind of allergy you have, particularly if you have chronic or recurrent symptoms, refer to the general pages for general information about allergies and potential causes. You can also refer to the suspected type of allergy.  

Contact Dermatitis: Allergy to Metal of a Necklace

Skin/contact allergies (including latex, plants, metals)

Medication allergies

Food allergies

Environmental allergies

Insect allergies

Again, if you have a significant allergic reaction that includes one or more of the following symptoms, go to an Urgent Care or ER to be treated

• Wheezing and/or shortness of breath

• Swelling of the throat, mouth, and/or tongue

• Rash or hives (a mild, minor rash can usually be treated at home with an antihistamine like Benadryl (preferred), Zyrtec (preferred), Allegra, or Claritin. You can also use a topical steroid - Hydrocortisone (common: Cortaid) if the rash is small and self-contained.

• Dizziness or syncope (passing out)

Of course, it is important to remove yourself from the precipitant

​Note

A note about allergy to intravenous (IV) contrast (for X-ray) - If you have any other allergies (asthma, allergic rhinitis, atopic dermatitis [eczema], and food allergies), you are at greater risk of having an allergy to contrast, used for radiologic exams.

Cleaning a house? Mixing chemicals?? Using more than one chemical? While not an "allergy", some substances cannot be mixed. When mixed, they create a toxic byproduct which can cause allergy and asthma-type symptoms. Bleach is a common household cleaner that is very effective in many circumstances, but it should not be mixed with other chemicals like ammonia, rubbing alcohol, vinegar, or Lysol (for all you nurses out there who were told to clean with BOTH of these products during COVID). These mixtures can be highly toxic and cause respiratory symptoms like coughing, shortness of breath, or asthma-like symptoms. When you clean, if you use more than one chemical, READ THE LABELS to be sure you are not mixing these substances.