Capsaicin is an effective component of pepper spray, which is mainly used as a self-defense tool and a non-lethal weapon for law enforcement officers. After being attacked by pepper spray, the attacker will involuntarily close his eyes, have difficulty breathing, and temporarily lose his ability to act. According to some papers, pepper spray can make more than 90% people give up their previous radical behavior. [1] Pepper spray will cause numbness, burning pain, erythema and other symptoms when it contacts the skin. But the main discomfort of pepper spray is poor breathing and irritation to cornea.

Generally speaking, the content of capsaicin in pepper spray is between 1%- 15%. Some people are allergic to capsaicin, but I haven't found any reports of symptoms after pepper spray allergy. For the situation mentioned in the question, it is certain that it is definitely not caused by "throwing sulfuric acid", because if it is sulfuric acid, the situation will be much worse than the picture. As for whether it is allergic or not, it needs to be checked by the hospital to be sure.

Although pepper spray has been widely used by the police in the United States, the controversy about pepper spray has never stopped. The report "Evaluation of the Effectiveness and Safety of Pepper Spray" of the US Department of Justice mentioned that after the introduction of pepper spray, the death rate of suspects and police officers decreased. The report mentioned 63 cases in which suspects died after being attacked by pepper spray, two of which were caused by pepper spray, but the suspects had asthma in advance. Another 6 1 case was caused by drug abuse and heart disease.

In a report on pepper spray by new york Citizen Complaint Review Board, it is mentioned that "when the police see the suspect having allergic reaction, they should immediately wash the victim's eyes with cold water".