Chloramin T

Code: k85
  • Sodium N-chloro-p-toluenesulfonamide trihydrate
  • Sodium N-chloro-4-toluenesulfonamide trihydrate
  • Sodium N-chloro 4-methylbenzenesulfonamide trihydrate
  • C7H7SO2N NaCl (3H2O)

A chemical, which may result in allergy symptoms in sensitised individuals.

Allergen Exposure

Geographical distribution
Chloramine (NH2Cl) and chloramine-T are 2 different chemicals. Chloramine is an intermediate product in the manufacture of hydrazine. Chloramine-T is a crystalline powder containing 11.5%-13% active chlorine (1).
Chloramine-T is a small-molecule oxidising agent that has been widely used as a disinfectant since the beginning of this century. This highly reactive derivative of chlorine has potent bactericidal properties. White or yellow crystals of the substance are prepared from p-toluenesulphonamide and sodium hypochlorite, and have a chlorine-like odour.
Often supplied in a powder form and commonly used in a 5% solution, Chloramine-T is used as a disinfectant in the food industry and in operating theatres. It is commonly used as a sterilizer, antiseptic, disinfectant and chemical reagent. Its use has increased, e.g., in hospitals, because of the increased risk of HIV infection and hepatitis (1). It may also be used in butcheries, kitchens, laboratories and dairies (9).  In low concentrations, it is a drug to control bacterial gill disease, external flexibacteriosis and parasites in fish. In bookbinding and book conservation, it can remove fox marks and stains from paper, and also serve for general bleaching purposes.
No allergenic epitopes from this substance have yet been characterised.

Clinical Experience

IgE-mediated reactions
Allergic asthma caused by chloramines-T is well-known and the reactions are IgE-mediated (1). There have also been case reports of immediate-type sensitisation to this agent associated with symptoms of rhinitis and urticaria. As the substance is a commercial rather than a domestic cleaning and bleaching agent, this sensitisation is occupational.
Occupational allergic contact urticaria and contact dermatitis have been reported (1-3).
Occupational asthma is the most frequently reported hazard. Bronchial asthma in workers who had handled Chloramine-T powder have been described (4-6). A patient exposed to chloramine-T experienced severe asthmatic symptoms when spraying chloramine-T solutions. The patient used chloramine-T as a sterilising agent in medical facilities (7). In statistics of the Finnish Register of Occupational Diseases (FROD; 1975-1998) and the patient material of the Finnish Institute of Occupational Health (FIOH; 1990-1998), 3 cases of asthma and one of rhinitis caused by chloramine-T were recorded in dental personnel (8). Occupational asthma and rhinitis have been described (9-10). Seven brewery workers developed asthmatic symptoms after using chloramine powder as a sterilising agent (11-12). Specific IgE antibodies were demonstrated in a patient who developed asthmatic symptoms after exposure to chloramine-T (13).
Late or immediate and late asthma, occasionally accompanied by fever and leukocytosis, can occur. A report indicates that a patient, after 4 years of exposure to chloramine-T, developed rhinitis and asthma. A male dairy worker developed rhinitis and asthma after 4 years of exposure to the chloramine-T. Skin tests with chloramine T were positive. RAST detected specific IgE, and bronchial provocation induced immediate and late bronchoconstriction (14).
Respiratory symptoms developed in 5 patients who were exposed to chloramine-T. Skin tests, performed in 4 patients, showed an immediate type of wheal and flare reaction followed by a late-type infiltrative reaction. In 3 patients, inhalation tests with chloramine-T were done. One patient showed asthmatic bronchial obstruction immediately after inhalation, followed by a late-type asthmatic reaction after some hours. Two patients exhibited only late-type reactions, 4 to 8 hour after the challenge. The late bronchial response lasted for several hours or even days and was accompanied by leukocytosis in all 3 patients and a slight fever in 1 patient (15).
Other reactions
Chlorine reacts with bodily proteins to form chloramines, mostly associated with swimming pools; the most volatile and prevalent in the air above swimming pools is nitrogen trichloride, which may result in occupational asthma in lifeguards and swimmers (16). This compound needs to be differentiated from Chloramine-T, an organic derivative of chlorine.
Compiled by Dr Harris Steinman,


  1. Kanerva L, Alanko K, Estlander T, Sihvonen T, Jolanki R. Occupational allergic contact urticaria from chloramine-T solution. Contact Dermatitis. 1997;37(4):180-1
  2. Hansen KS. Occupational dermatoses in hospital cleaning women. Contact Dermatitis. 1983;9(5):343-51
  3. Dooms-Goossens A, Gevers D, Mertens A, Vanderheyden D. Allergic contact urticaria due to chloramine. Contact Dermatitis. 1983;9(4):319-20
  4. Blomqvist AM, Axelsson IG, Danielsson D, Kiviloog J, Ulander A, Zetterstrom O. Atopic allergy to chloramine-T and the demonstration of specific IgE antibodies by the radioallergosorbent test. Int Arch Occup Environ Health. 1991;63(5):363-5
  5. Blomqvist A, Sundell L, Axelsson G. A patient with IGE-mediated allergy to chloramine T received occupational injury compensation. [Swedish] Lakartidningen. 1989;86(48):4262-4
  6. Beck HI. Type I allergy to chloramines. [Danish] Tandlaegebladet. 1983;87(3):98-9
  7. Dellabianca A, Vinci G, Biale C, Pisati A, Moscato G. Asthma caused by sodium p-toluene-n-chloro-sulfonamide: observations on a clinical case. [Italian] G Ital Med Lav. 1988;10(4-5):207-10
  8. Piirila P, Hodgson U, Estlander T, Keskinen H, Saalo A, Voutilainen R, Kanerva L. Occupational respiratory hypersensitivity in dental personnel. Int Arch Occup Environ Health. 2002;75(4):209-16
  9. Kujala VM, Reijula KE, Ruotsalainen EM, Heikkinen K. Occupational asthma due to chloramine-T solution. Respir Med. 1995;89(10):693-5
  10. Keskinen H, Nordqvist E, Tuppurainen M, Sala E, Nordman H. Asthma and rhinitis due to chloramine T-powder in instrument maintenance personnel. [Finnish] Duodecim. 1995;111(10):921-5
  11. Bourne MS, Flindt ML, Walker JM. Asthma due to industrial use of chloramine. Br Med J. 1979;2(6181):10-2
  12. Charles TJ. Asthma due to industrial use of chloramine. [Letter] Br Med J. 1979;2(6185):334
  13. Kramps JA, van Toorenenbergen AW, Vooren PH, Dijkman JH. Occupational asthma due to inhalation of chloramine-T. II. Demonstration of specific IgE antibodies. Int Arch Allergy Appl Immunol. 1981;64(4):428-38
  14. Blasco A, Joral A, Fuente R, Rodriguez M, Garcia A, Dominguez A. Bronchial asthma due to sensitization to chloramine T. J Investig Allergol Clin Immunol. 1992;2(3):167-70
  15. Dijkman JH, Vooren PH, Kramps JA. Occupational asthma due to inhalation of chloramine-T. I. Clinical observations and inhalation-provocation studies. Int Arch Allergy Appl Immunol. 1981;64(4):422-7
  16. Thickett KM, McCoach JS, Gerber JM, Sadhra S, Burge PS. Occupational asthma caused by chloramines in indoor swimming-pool air. Eur Respir J. 2002;19(5):827-32 


As in all diagnostic testing, the diagnosis is made by the physican based on both test results and the patient history.