Asthma related to inhalation of Plantago ovata

BACKGROUND: Psyllium is the seed of the plant Plantago ovata, which is wide ly used in nonprescription laxatives. It has been reported that psyllium po wder may act as an inhalant allergen, especially in the workplace. A patien t with asthma due to inhalation of P. ovata seed powder is described, being highlighted the allergenic potential of this substance frequently used as a laxative. We report a 31 year-old atopic woman, who handled and prepared at home, twice daily, a laxative containing P ovata seeds (Plantaben(R)) pr escribed to her paralytic mother. METHODS AND RESULTS: Skin prick test to psyllium powder extract was positiv e, Specific IgE antibodies to psyllium were positive as determined by ELISA . Methacholine inhalation test revealed mild bronchial hyperresponsiveness (PC20 = 1.5 mg/ml). Specific bronchial challenge to psyllium powder elicite d an isolated early asthmatic response. The allergens in psyllium were inve stigated by SDS-PAGE and immunoblotting, being identified several allergeni c components with an apparent molecular weight of 66, 60, 36-20 and 14 kDa. No cross-reactivity was found between P. ovata seed and P. lanceolata poll en, as determined by ELISA-inhibition. CONCLUSION: Psyllium may act as a potent inhalant allergen capable of elici ting asthma symptoms, not only in an occupational context, but also in a do mestic environment, affecting consumers of this laxative or relatives who h andle it.