Airborne allergic contact dermatitis to artichoke (Cynara cardunculus L.) in a greengrocer.

Artichokes (Cynara cardunculus L.) are known to cause allergic contact dermatitis (ACD) on exposed skin by direct contact but also by airborne spread.1-3 Formerly known as Cynara scolymus L., or Cynara cardunculus subsp. scolymus (L.) Hegi, or Cynara cardunculus var. scolymus (L.) Benth., or by other names all now regarded as synonyms, these vegetables belong the Compositae (or Asteraceae) family. In common with many other members of this family, they contain sesquiterpene lactones (SLs) as allergens.2 A 35-year-old male greengrocer was referred from the Emergency Ward for severe ‘angioedema-like’ periorbital eczema (Figure 1). He reported that similar episodes had been relapsing for the last 2 years, around October–November and March–April, whenever he handled two unidentified/unnamed Italian seasonal varieties of autumnal (‘rifiorenti’) and spring (‘uniferi’) artichokes. The patient was patch tested to the SIDAPA (Società Italiana di Dermatologia Allergologica Professionale e Ambientale) baseline series,4 Compositae mix 6% pet (Tanacetum vulgare 1%, Arnica montana 0.5%, Achillea millefolium 1%, Tanacetum parthenium 1%, Matricaria chamomilla 2.5%, Smart Practice, Italy), SLs mix 0.1% and fragments of fresh artichoke (stem and bract) of unknown variety, which was brought in by the patient from his grocery store and was applied as is under occlusion. He reacted positive to artichoke stem (+? at Day 3 and + at Day 4) and bract (− at Day 3 and + at Day 4), SLs mix (++ at Day 3 and ++ at Day 4) and Compositae mix (− at Day 3 and + at Day 4). Fresh artichoke was patch tested in five healthy controls with negative result. Prick testing showed reactivity to house dust mites, although the patient denied respiratory allergies and childhood atopic eczema. Prick testing with fresh artichoke elicited no reaction. Our patient was patch test positive to Compositae mix, SLs mix and artichoke as is. The main SLs allergens in artichokes are reported to be cynaropicrin, grosheimin and its derivative 8-deoxy-11,13-dihydroxygrosheimin2 but the specific SLs responsible for ACD to artichoke and their possible co- or cross-reactivity with other well-known SLs allergens remain unknown. Our patient's manifestations skewed towards an airborne ACD. In fact, his hands were spared while exposure to artichokes triggered rather acute facial reactions that had eventually led him to the Emergency Ward. Similarly, Samaran et al. described a 71-year-old woman who developed acute ‘angioedema-like’ periorbital eczema shortly after handling artichokes.2 Meding et al. reported a 44-year-old male vegetable seller who suffered from recurrent facial eczema at work and developed an episode of acute facial eczema associated with a feeling of obstruction in the throat after cooking and eating artichokes.5 We recently described an artichoke and SLs mix allergic greengrocer with chronic recurrent severe facial eczema that flared both when he was occupationally exposed to artichokes and when he travelled to Pakistan where he was exposed to Parthenium hysterophorus L.3 In his case, co-reactivity to different SLs allergen/s in different Compositae was postulated although not demonstrated. In conclusion, although artichokes are an infrequently reported cause of ACD, they contain moderate to strong allergenic SLs6 and our case confirms that they can induce severe airborne ACD and might be, in particular, an important and underrecognized cause of occupational ACD. Giulia Gasparini: Conceptualization; writing – original draft; validation; writing – review and editing; investigation. Rosella Gallo: Conceptualization; writing – review and editing; investigation; supervision. Ilaria Trave: Investigation; validation. Niccolò Capurro: Investigation; validation. Aurora Parodi: Writing – review and editing; validation; supervision. Thanks are due to Lucia Volpicelli and Ornella Perversi for their expert technical assistance. The authors declare no conflicts of interest. The patient gave written consent to publication of his images.