More Than a Rash: What is a Skin Sensitizer?  

February 7, 2022

What is a skin sensitizer? – Chemscape

A skin sensitizer is a chemical that can lead to an allergic response following skin contact. Much like touching poison ivy, the result is more than skin irritation at the location of contact and worsens every time you have contact with the plant.  

When you become sensitized to a substance, your immune system develops a memory to the specific chemical. With every subsequent exposure, it takes less of the substance to initiate the allergic reaction and the result may be more severe.   

Skin sensitization appears as a red, itchy, bumpy rash and is also known as allergic contact dermatitis (ACD). It is one of the most common hazards in the workplace but can be difficult to diagnose. The impact of sensitization can cause the affected worker to avoid the chemical by changing jobs or rotating to another job site.

What products are considered skin sensitizers?

The classification of a product as a skin sensitizer is based on human experience, a human skin sensitization test, or animal testing.  

Sensitizers are present environmentally and occupationally in many different industries including pharmaceuticals, chemical production, biofuels, and food and beverage; they are also in many consumer products.  

Approximately half of occupational allergic contact dermatitis (ACD) cases are due to rubber, nickel, and fragrances. The rest come from preservatives, cosmetics, chromate, aromatic amines, epoxy, and other resins. Well-known examples of sensitizers are toluene diisocyanate, nickel compounds, and poison ivy.  

What factors affect exposure to a skin sensitizer?  

Health risks from skin sensitizers are linked to skin contact, ingestion, and inhalation. Exposure of the skin to extreme temperature, solar radiation, and biological risks can also contribute to the risk of developing ACD.  

Many factors affect dermal sensitization including how long you were exposed to a substance and the intensity of exposure, chemical properties, and of course, individual susceptibility.  Immune system hypersensitivity can usually be resolved with topical corticosteroids and trigger avoidance. 

How do you suspect a skin sensitization reaction?  

Exposure to a skin sensitizer should be suspected when a worker has symptoms of dermatitis immediately upon entering an area where the product is used. These symptoms disappear when the employee leaves the worksite for an extended period of time, like a weekend or vacation, and reappear when the employee returns to the workplace.  

Distinguishing between irritation and sensitization can be difficult. The key difference is the location of symptoms on the body (at the contact site versus generalized) and whether delayed reactions occur. Signs of irritation contact dermatitis (ICD) include chronic eczema (dry, itchy skin and rashes) with peeling or cracking skin, while signs of ACD include acute eczema (quick and intense onset of skin inflammation) with blistering.  

Presently, there is no practical way to calculate workplace exposure threshold concentrations for skin sensitization because the data is associated with dermal applications and OELs are generally calculated for the inhalation route of exposure. Many products aren’t classified as sensitizers due to the lack of data and information on the product.  

Contact Chemscape Safety Technologies today to learn how we can help reduce workplace hazards and elevate the health and safety standards of your organization.