The most relevant allergens from the P. acerifolia pollen have been determined. A major allergen, specific of this pollen, and named Pla a 1, has been purified and characterized.

Stallergenes Greer Spain.

Pla a 1 and Pla a 2 were responsible for 79% of the IgE-binding capacity against P. acerifolia pollen extract. A high correlation has been found between the IgE response to nPla a 1 (R = 0.80; P < 0.001) or nPla a 2 (R = 0.79; P < 0.001) vs. P. acerifolia extract as well as between natural and recombinant Pla a 1 (R = 0.89; P < 0.001). Skin testing showed no significant differences between extract and nPla a 2, whereas a higher reactivity was found with nPla a 1. In contrast, rPla a 1 revealed markedly reduced sensitivity in comparison with extract by skin prick test and specific IgE. The sensitivity of the mix Pla a 1+Pla a 2 was 100% and 87.5% for monosensitized and polysensitized patients, respectively, with no false-positive reactions detected. Conclusion Pla a 1 and Pla 2 are sufficient for a reliable diagnosis of P. acerifolia in most patients and induce comparable skin test reactivity as a whole extract.

Contact sensitization by topical steroids IS uncommon but sufficiently documented m the literature (I, 2). The climcal manifestation IS usually a dermatosis that IS worsemng or simply not 1mprovmg with topical treatment (3). Usually, a suspected contact allergic reaction to a topical corticosterOid cannot be demonstrated by a patch test with the medicament Itself (4). Many patients undiagiiosed by a patch test to the actual medicament show a clear positive allergic reaction to a patch test with tixocortol piva-Jate 1% pet. (3, 4).Tixocortol p1valate IS probably a denvate, formed m the skm, after the application of creams or omtments onginally contammg other topical stermds, such as hydrocortisone or clobetasol propwnate (4, 5). Patch testing with tixocortol p1valate at I% may be useful for demonstrating topical stermd sen-Sitivities, but It IS not mfallable (3). Moreover, tixocortol p1valate also has its own capacity for contact sensitization (6, 7).Tixocortol p1valate IS not a medicament employed for the treatment of cutaneous disases m Spam, but it IS used for the treatment of rhmitis of different aetiologies. Case ReportA 38-year-old woman developed an endogenous chrome rhmitis m 1981. Complete mmunologJcal studies confirmed Its non-allergic aetiology. She was treated successfully With a commercial spray (Tiov-alone®) contammg 0.1 g of tixocortol p1valate m 10 mi. After a short penod of time, she complamed of a severe mtolerance to this spray and changed to conventional oral antih1stammes, followmg wh1ch her nasal symptoms remamed controlled for some years.In 1987, a relapse of her rhmitis was retreated with Tiovalone® spray. A severe local endonasal mtolerance reappeared. She never had any cutaneous dermatitis on the skm of the nose, upper lip or face. On th1s second visit, she also described a chrome relapsmg dermatitis of the earlobes and abdommal skm, w1th mtolerance to metallic Jewellery for many years. Only because of this new climcal mformation did we proceed to patch test her, obtammg an unexpected allergic reactiOn to tixocortol p1valate. Patch tests GEIDC standard senes mckel sulphate 5% pet. turpentine 10% o.o. benzalkomum chlonde 0.1% pet. tixocortol p1valate 1% pet. 96 h ++ + + ++The patient had used topical steroid creams many times to treat her mckel dermatitis. She had never complamed of adverse reactions to those treatments. Patch tests with a senes of different topical stermds to look for cross-reactions were not performed.We therefore describe a climcal case of contact allergy to tixocortol p1valate itself, employed as an

No abstract