nSus s Pepsin, Swine

Code: k213
Occupational allergen
An occupational allergen, which may result in allergy symptoms in sensitised individuals.

Allergen Exposure

Geographical distribution
Pepsin, an acidic gastric protease, is one of the 3 principal protein-degrading, or proteolytic, enzymes in the digestive system, the other 2 being chymotrypsin and trypsin. Pepsin in the stomach begins the digestion of proteins by splitting them into smaller pieces. Pepsin cleaves proteins preferentially at carboxylic groups of aromatic amino acids such as phenylalanine and tyrosine. It will not cleave at bonds containing valine, alanine or glycine. Pepsin is secreted in an inactive form as a zymogen precursor, pepsinogen, which is activated by stomach acid.

There are several Pepsins, designated A, B, C, and D. Pepsin A, the major type, has a molecular weight of 35 kDa. The optimum pH for Pepsin activity is 2 – 4.
Pepsin, available as freeze-dried powder and obtained from the stomachs of hogs and calves, is used in the laboratory analysis or hydrolysis of various proteins. Pepsin (along with other enzymes such as chymosin and rennet) is also used in the preparation of cheese and other protein-containing foods. Pepsin has also been employed as a digestive aid.
Individuals exposed to Pepsin include cosmetics, textile, animal pelt, food, chemical, pharmaceutical and laboratory workers, medical staff, and maintenance persons and cleaners.
The allergens have yet to be characterised.

Clinical Experience

IgE-mediated reactions
Pepsin may uncommonly induce symptoms of occupational allergy, in particular asthma, in sensitised individuals (1). Safety precautions taken when using this substance may have resulted in infrequent reports of sensitisation to it.

Occupational asthma was described in a 39-year-old male cheese worker, who had for 2 years experienced asthma and rhinitis elicited by work exposure to both Pepsin and Lysozyme. The presence of skin-specific IgE was demonstrated to both. One minute after Pepsin exposure, the patient developed rhinoconjunctivitis, cough, dyspnoea, wheezing, dysphonia, and glottic oedema. Lung function tests confirmed a drop in lung function. Serum-specific IgE was positive to Lysozyme but negative for Pepsin and chymosin (2).

Occupational asthma as a result of exposure to Pepsin has been described in detergent industry workers (3). Occupational asthma may have an immediate, severe IgE-mediated, and a delayed, severe IgE-mediated component – the so-called dual asthmatic response, which was demonstrated in a Pepsin-hypersensitive individual following an inhalation challenge with Pepsin powder (4).

Exogenous allergic alveolitis in workers engaged in the manufacture of Pepsin has been described (5-6).

Compiled by Dr Harris Steinman, harris@zingsolutions.com


  1. Hartmann AL, Wuthrich B, Baur X. Allergic asthma from enzymes in drugs. [German] Schweiz Med Wochenschr 1984;114(25):916-7
  2. Anibarro Bausela B, Fontela JL. Occupational asthma in a cheese worker. Allergy 1996;51(12):960-1
  3. Quirce s, Sastre J. Occupational asthma [Review]. Allergy 1998;53:633-641
  4. Cartier A, Malo JL, Pineau L, Dolovich J. Occupational asthma due to pepsin. J Allergy Clin Immunol 1984;73(5 Pt 1):574-7.
  5. Krasniuk EP, Petrova IS, Pilinskii VV. Exogenous allergic alveolitis in workers engaged in the manufacture of pepsin. [Russian] Lik Sprava 2001;(4):168-71
  6. Hartmann AL. Contribution of the Allergy Clinic to occupational asthma and allergic alveolitis. [German] Schweiz Rundsch Med Prax 1998;87(40):1316-24

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