Botanical Briefs: Primula obconica Dermatitis
Primula obconica, a household plant originally found in China that was introduced in Europe in the 1880s, has been reported to cause plant-induced contact dermatitis (CD). The condition more commonly is reported in Europe and less frequently in the United States, where the plant is not commonly included in patch testing protocols. Clinical features of P obconica CD can include facial and hand as well as fingertip dermatitis. The main allergens known to cause these findings are primin and miconidin. Treatment of P obconica CD mainly involves avoiding contact with the plant and applying a topical steroid.
Practice Points
- Primula obconica is a household plant that can cause contact dermatitis (CD). Spent blossoms must be pinched off to keep the plant blooming, resulting in fingertip dermatitis.
- In the United States, P obconica is not a component of routine patch testing; therefore, it might be missed as the cause of an allergic reaction.
- Primin and miconidin are the principal allergens known to be responsible for causing P obconica dermatitis.
- Treatment of this condition is similar to the usual treatment of plant-induced CD: avoiding exposure to the plant and applying a topical steroid.
Cultivating the plant outdoors during the winter in milder climates can potentially decrease sensitivity because allergen production is lowest during cold months and highest during summer.11 Because P obconica is commonly grown indoors, allergenicity can persist year-round.
Pharmacotherapy—Drawing on experience treating CD caused by other plants, acute and chronic P obconica CD are primarily treated with a topical steroid or, if the face or genitals are affected, with a steroid-sparing agent, such as tacrolimus.12 A cool compress of water, saline, or Burow solution (aluminum acetate in water) can help decrease acute inflammation, especially in the setting of vesiculation.13
Mild CD also can be treated with a barrier cream and lipid-rich moisturizer. Their effectiveness likely is due to increased hydration and aiding impaired skin-barrier repair.14
Some success in treating chronic CD also has been reported with psoralen plus UVA and UVB light therapy, which function as local immunosuppressants, thus decreasing inflammation.15
Final Thoughts
Contact dermatitis caused by P obconica is common in Europe but less common in the United States and therefore often is underrecognized. Avoiding contact with the plant should be strongly recommended to allergic persons. Primula obconica allergic CD can be treated with a topical steroid.
