Primin

Primin, a benzoquinone derivative that occurs mainly in the glandular hair secretion of Primula obonica(cup primrose or poison primrose), which is often kept as a potted plant in households. The allergen content of the individual plant is highly dependent on the season, light, weather and other growing conditions. The breeding of completely primin-free varieties has not yet been successful.

Primin is one of the strongest known allergens (Bongiorni L et al. 2015). It was therefore previously also frequently used in humans as a model substance for the study of allergic reactions. The benzoquinone structure indicates a distinct sensitizing potency, which is modified by the length, position and configuration of the aliphatic side chain. In principle, sensitization is also possible aerogenically.

In a larger (Italian) collective of patients with potential contact sensitization (n=24,000), Bongiorni L et al. (2015) demonstrated primin synsensitization of 1.9%, with women being more frequently sensitized (2.6%) than men (0.5%). In certain areas of Italy (Pordonne), even higher rates of sebisbilization (up to 6%) have been detected.

Cross-reactions with structurally similar quinones occurring in other plants or wood species, e.g. Dalbergia species, teak (Tectona grandis) or Pao ferro (Macherium skleroxylon) are possible but rarely observed.

S.u. primrose dermatitis

The medically and cosmetically used Primula species (Primula veris, Primula elatior and Primula vulgaris - see below cowslip) contain only small amounts of Primin.

1. Bongiorni L et al (2015) Primin sensitization in north-eastern Italy: a temporal trend from 1996 to 2012. contact dermatitis 73:108-112.
2. Hervella-Garcés M et al (2016) en representación del Grupo Español de Investigación en Dermatitis de Contacto y Alergia Cutánea (GEIDAC).the Spanish standard patch test series: 2016 update by the Spanish Contact Dermatitis and Skin Allergy Research Group (GEIDAC). Actas Dermosifiliogr 107:559-566.
3. Zachariae C et al (2007) Primin in the European standard patch test series for 20 years. Contact dermatitis 56:344-346