Asthma caused by tea dust


Occupations
  • Food industry
Agents
Tea
 
Incidence
Incidence: rare - a few cases have been described. The mechanism remains to be established, but may be due to a type of irritation. There are no reports that IgE is involved. Smoking has sometimes been desribed as a co-factor.
 
Conditions
The cause is the leaf dust and debris from dry tea and a type of packaging material used when the tea is put into sacks. Of the many components of the tea leaf, epigallocatechine gallate (EGCg;mw:458 daltons) appears to be the most allergenic.
 
Symptoms
Rhinitis, cough, sporadic coryza, breathing difficulty and asthma.
 
Diagnostic methods
Skin tests are negative. RAST/CAP RAST with tea.
 
Bronchial provocation test (in hospital) with tealeaf dust is positive with both an immediate and a delayed reaction.
 
Both skin prick tests and bronchial provocation tests with EGCg give rise to an immediate reaction.

References

  1. Chest 1994,106:1801
  2. Int. Arch. Occup. Environ Health 1985,56:57
  3. Thorax 1990,45:203
  4. Eur. Resp. J. 1988,1:769
  5. Br. J. Ind. Med. 1970,27:181

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