Autosensitization dermatitis associated with propolis-induced allergic contact dermatitis

Journal of Drugs in Dermatology, May, 2006 by Seung Yoon Lee, Doo Rak Lee, Chung Eui You, Mi Youn Park, Sook Ja Son

Abstract

Propolis is a beehive product known for its anti-inflammatory properties. With its growing use, propolis-induced contact dermatitis is increasing. While the dermatitis mostly occurs on areas directly exposed to propolis, our case presented an additional eczema at a site distant from the primary propolis-induced contact dermatitis twice in the same individual. We diagnosed it as an autosensitization dermatitis associated with propolis-induced allergic contact dermatitis.

Case Report

A 59-year-old Asian woman presented with crythematous, swelling patches and plaques with scale on the feet. In addition, the proximal aspect of the right shin demonstrated well-demarcated, crythematous, scaly patches and macules (Figure 1). The patient reported that she had been applying plant extract on her feet for a few days prior to the eruption as an oriental folk medicine to reduce pruritus caused by tinea pedis. She couldn't recall the exact ingredients of the plant extract. She was sure that she had not applied the extract on the right shin. Any use of topical antifungal agent was denied. The histopathologic features of both lesions corresponded with contact dermatitis. We diagnosed the lesion on her right shin as an autosensitization dermatitis associated with contact dermatitis induced by unknown plant extracts. The lesions improved after use of oral antihistamine and topical steroid agents. After 3 months, she came back with erythematous, swelling, oozing patches on her left ear (Figure 2A). Additionally, mildly erythematous, scaly patches and papules were noted on the skin around the medial canthus of the left eye and on both nasolabial areas (Figure 2B). This time she applied propolis on her left ear for itching of unknown origin, but not on the periorbital or nasolabial area. She denied the presence of any visible skin lesion on the left ear before application of propolis. Histopathologic examination revealed a contact dermatitis again, and the lesions healed after the same treatment as before. After a 2-week washout period for oral antihistamines since complete healing of the lesions was achieved, she was patch tested with propolis (10% in petrolatum) and with the European standard series including balsam of Peru and fragrance mix. The patch test was positive to propolis(+++) and fragrance mix(++), but negative to balsam of Peru. The similarity between her two episodes made us suspect that the previous one might have been also induced by propolis. On further questioning about the previously applied plant extract, she reported that she had mixed several droplets of propolis to the extract, and that she had previously omitted mentioning this as she considered propolis natural and completely harmless.

Discussion

Propolis is a resinous beehive product that has been used in folk medicine for a long time. Known for its antiseptic, anti-inflammatory, antioxidant, spasmolytic, and local anesthetic properties, it has been used for wounds, pruritus, burns, and many other skin diseases. (1) These days, consumers tend to prefer using "natural" products including propolis. The belief that such preparations are completely harmless enabled propolis to find its way into many cosmetic products and pharmaceuticals in various forms. With this trend, propolis-induced allergic contact dermatitis is increasing in the general population whereas previously it most often occurred in individuals exposed to propolis occupationally, such as beekeepers. (2) The main sensitizers of propolis are LB-1 (a mixture of 3 caffeic acid pentenyl esters) and phenylethyl caffeate, which are derived from poplar bud secretion, the bee's major source of propolis. (1) Besides these, propolis is composed of over 46 constituents. (1) Among them, several compounds are common in balsam of Peru, to which is ascribed the positive reaction to balsam of Peru in certain proportions of propolis-sensitive individuals. But this cross-reaction does not always happen, as shown in our case. (3)

Propolis-induced contact dermatitis usually develops in the areas exposed to propolis, such as the hands of beekeepers (4) or violin makers, (5) cosmetics-applied areas, (6) and previous skin lesions treated with propolis. (7) A few cases of airborne contact dermatitis due to propolis have been reported recently in which the dermatitis occurred in the areas not exposed to propolis. (8) Our case presented similarly to airborne contact dermatitis in that the secondary dermatitis developed on a site unexposed to propolis and distant from the primary propolis-induced contact dermatitis lesion. However, the possibility of our case being an airborne contact dermatitis seemed weak because the patient had not been in a forest or at a bee-farm recently and because the propolis was sealed tightly in a glass bottle not able to vaporize into the air.

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To our knowledge, autosensitization dermatitis associated with propolis-induced allergic contact dermatitis has not been reported yet. Its unusual manifestation may render the correct diagnosis difficult, particularly because patients tend to neglect reporting the use of propolis in confidence of its innocence. Therefore, physicians should carefully ask about any use of propolis-containing products when allergic contact dermatitis is suggested without any suspected contact history.