t16 White pine

Not to be confused with the Australian pine tree (Casuarina equisetifolia) t73

IgE-mediated reactions

Pinus pollen can induce asthma, allergic rhinitis and allergic conjunctivitis (1-3).Pinus pollen allergy has been generally considered to be rare.

Although Pine pollen is released in large quantities, IgE-sensitisation to it has been found to occur in only 1.5%-3% of atopic patients in a northern Arizona private allergy practice, and in French studies (1, 2).

This study reports that the incidence of positive skin testing to White pine in New England patients with spring seasonal allergic rhinitis was 6/61 (6%). Two of 4 patients challenged intranasally had a positive challenge (4).

A Spanish study suggests that Pine tree pollen is a significant aeroallergen and should be considered in investigations of pollen-allergic individuals. In this study, Pinus pollen (Pinus pinaster and Pinus radiata) was shown to be among the dominant pollens in an area of Spain. The majority of the patients were monosensitisated to Pinus pollen and suffered from seasonal rhinoconjunctivitis (3). The sensitising Pine pollen would in all instances depend on which species of Pine tree is present in the vicinity.

Other studies have shown that Pine tree pollen may be a significant aeroallergen. In a study of aeroallergen sensitisation rates in children of the military in Texas, of 345 children who were skin prick-tested to a 51-allergen panel, 6.4% were positive to Pine (5).

As extensive cross-reactivity exists between Pine tree (P. radiata) and White pine tree (P. strobes), the latter should be found to generate similar clinical patterns to those the former generates

Other reactions

Allergic contact dermatitis to White pine sawdust has been described (6). Contrary to the rarity of sensitisation to Pine pollen, workers processing Pine in sawmills showed a very high frequency of IgE sensitisation to the extract of Pine wood dust. This frequency was significantly greater than that of the sensitisation to Oak of workers processing Oak. (7) Airborne allergic contact dermatitis from Pine dust has been documented (8).

No allergens from this plant have yet been characterized.

Cross-reactivity

An extensive cross-reactivity among the different individual species of the genus could be expected (9).

As extensive cross-reactivity exists between Pine tree (P. radiata) and White pine tree (P. strobes), the following cross-reactivity patterns should be considered applicable to White pine tree.

IgE antibody studies have demonstrated that pollen extracts from Olive, Birch, Mugwort, Pine, and Cypress contain proteins that share common epitopes recognizable by sera from Olive-allergic individuals (10). Enzyme immuno-assay inhibition studies have revealed that leached P. radiata pollen proteins could partially inhibit serum IgE binding to Rye grass-specific IgE. This provides preliminary evidence for allergen cross-reactivity between these 2 unrelated species (11).

Importantly, allergy to Pine nuts can occur with no symptoms of sensitization to Pine pollen. Immunoblot experiments have demonstrated the presence of IgE antibodies in serum against several components of Pine nuts and pollen, with the presence of some cross-reacting components. The authors of this study suggest that development of Pine pollinosis may require a longer period of exposure to allergens, and that given the cross-reactivity between Pine nut and Pine pollen extracts, co-sensitization to these 2 allergens could be possible (12).

Last reviewed: April 2022