w12 Goldenrod

Solidago encompasses approximately 130 species, most of which are found in North America, though some are common to Europe and northern Asia as well. (1) Solidago is also found in South America and other parts of the world, where some species within the genus are cultivated as ornamentals. The closely related species, Canada goldenrod, S. canadensis, is a common plant, found throughout Canada and the United States, from coast to coast. (1) Several species, such as Late Goldenrod, S. gigantea, have a high latex content of the leaves. (1, 2)

Goldenrod is a perennial weed often found along roadsides and in open fields. It has a single woody stem that grows as high as 2m. It spreads by seed and creeping roots. It may be grown as an ornamental plant. The alternate, three-veined leaves at the base of the plant are bright green and oval-shaped, drawing to a point, while the leaves on the stem are smaller and wholly oval in shape. The leaves have either toothed or smooth edges.

The stems produce scented spikes of simple golden-yellow flowers, which have clusters of stamens, from mid- to late summer (August and September). Flowers are yellow, with numerous small heads with overlapping involucral bracts, having 10 to 17 rays. (1) The ornamental Goldenrod is smaller, growing to 0.6m and in flower from July to October. The flowers are small (6mm) and are produced in profuse clusters. The flowers are hermaphrodite (have both male and female organs). As Goldenrod is insect-pollinated, the pollen grains are much heavier than those of ragweed and other plants that have airborne pollens associated with allergic symptoms. The plant is also self-fertilising. The seeds ripen from August to October.

In areas where Ragweed exists, as ragweed anthesis wanes, Goldenrods such as S. speciosa (Showy Goldenrod) and S. sempervirens (Seaside Goldenrod) are still producing large amounts of pollen, and captured Goldenrod pollen will exceed that of Ragweed. (1)

Goldenrod is found along roadsides, in open fields, dry woods, grasslands, hedge banks and dunes.

Goldenrod has been used topically for healing wounds, and by American Indians as a salve for rattlesnake bites. Tea can be made from the leaves.

Allergen description

No allergens from pollen from this plant have yet been characterised.

The leaves are reported to have a high latex content which may be an important occupational sensitiser. IgE antibodies from individuals with Goldenrod allergy bound Goldenrod proteins ranging from 20 kDa to 130 kDa in Western blots, and evidence for latex and Goldenrod cross reactivity was identified. (3)

Potential Cross Reactivity

An extensive cross-reactivity among the different individual species of the genus could be expected, as well as to a certain degree among members of the family Asteraceae, which includes Solidago (Goldenrod), Ambrosia (Ragweed), Chrysanthemum, Matricaria chamomilla (Chamomile) and Artemisia vulgaris (Mugwort). (4, 5, 6) Cross-reactivity between ragweed and goldenrod is minor. (7)

Extensive cross-sensitisation was observed to pollen of several members of the Compositae family (e.g., Matricaria, Chrysanthemum, Solidago) and to pollen of the Amaryllidaceae family (Alstroemeria and Narcissus). (8)

Clinical Experience

IgE mediated reactions

Anecdotal evidence suggests that asthma, allergic rhinitis and allergic conjunctivitis are common following exposure to pollen from Goldenrod, particularly in an occupational setting, e.g., that of flower sellers; however, few specific studies have been reported to date. (8, 9, 10) However, whether Goldenrod is a significant cause of hay fever remains debatable and asthma has not been reported. (1)

Thirty of 100 individuals with hayfever as a result of Ragweed were shown to be sensitised to Goldenrod. (10)

Of 14 consecutive patients seen at an allergic clinic in the Netherlands, with complaints varying from allergic rhinoconjunctivitis and asthma to urticaria due to the handling of flowers, 12 reported Solidago as the responsible plant. Eleven were shown to have serum specific IgE directed at Solidago and 12 were skin prick test positive. (8)

In a study of 130 patients with allergic rhinitis in three different sites in Eskisehir, Turkey, 5.% were skin prick test positive to Goldenrod. (11) In a Korean study of 133 patients with allergic symptoms evaluated using 3 different kits for detection of allergen specific IgEs, 7-9% were sensitised to Goldenrod depending on the test used. (12)

Although Goldenrod is mainly insect-pollinated, the pollen has been detected in gravimetric sampling e.g. in the Fairbanks area, Alaska. (13)

Other reactions

Allergic contact dermatitis after systemic administration has been reported. (14)

Last reviewed: June 2022.