1- chloroacetophenone sensitization

CNC is a formulation of chloroacetophenone. Like CN, CNC has a pronounced lacrimatory effect, resulting in a natural reflex to shut the eyes. It is similarly irritating to the skin, especially the face and such exposed portions of the body where sweat accumulates. The same rashes caused by CN will be caused by CNC. CNC has a slightly more powerful choking effect than CN. Eye toxicity remains about the same as CN. Some sensitive individuals may experience nausea upon exposure. CNC can form lethal concentrations in closed or confined spaces, although concentrations in open are highly unlikely ever to do so. 

Sporadic cases of dermatitis due to primary irritation by a-chloroacetophenone have been reported. Allergic contact dermatitis to this substance in chemical Mace has been documented by patch test evaluation, and it is said to be a potent skin sensitizer. ... 

Toxicology. a-Chloroacetophenone is a potent lacrimating agent and an irritant of mucous membranes it causes dermatitis of both primary irritation and sensitization type. 

Chung, C.W., Giles, A.L. (1972). Sensitization of guinea pigs to alpha-chloroacetophenone (CN) and ortho-chlorobenzylidene malononitrile (CS), tear gas chemicals. J. Immunol. 109 284-93. 

Many contact sensitizers also have irritant properties. Patch testing with such sensitizers at high concentrations can cause an irritant reaction or a chemical burn, which seems to facilitate active sensitization. However, only a few sensitizers can cause chemical burns without occlusion, e.g., formaldehyde, chromic acid, amines, chloroacetophenone, some plastic monomers, and methylisothiazolinones. Even one single contact with these chemicals can both cause a chemical burn and induce sensitization, with a subsequent possible development of an allergic contact dermatitis (Bruze et al. 1990 Kanerva 1994). Therefore, when a potential sensitizer has caused a chemical burn, the patient should be patch tested with the sensitizer after healing of the burn, independent of any subsequent development of an eczema. 

Chloroacetophenone is contained in tear gases (lac-rimators). This substance has an important irritative potential but can also be a sensitizer. 

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