You can use Benzalkonium chloride as a skin detergent and disinfectant. It is also in a wide range of products in the home, including cosmetics, deodorants and mouthwashes.
Symptoms of an allergic reaction to benzalkonium chloride include a rash on the skin that has come in contact with it, itching skin and hives, according to "Fisher's Contact Dermatitis."
Because benzalkonium chloride can be found in everything from Bactine to artificial tear eye drops, it can be difficult to avoid. Antihistamines can help control an allergic reaction if you do come in contact with it.