Long Island Dermatological Society

Read My Lips

May 01, 2005


Patient #1 was a 12 year old boy who presented with a 3 day history of a pruritic rash on the lips and perioral area which was so uncomfortable it was difficult for him to open his mouth.  He had a history of severe sensitivity to poison ivy, but no recent history of outdoor plant exposure.  The rash responded to use of class 1 topical corticosteroids for several days followed by tapering.

Patient #1 (click image to enlarge)

Patient #2 was a 42 year old woman who presented with a 4 day history of  an erythematous, pruritic eruption of the lips and chin.  She was seen by her primary care physician who placed her on oral acyclovir and hydroxyzine without improvement.  She had a history of poison ivy, but denied recent exposure.

Patient #2 (click image to enlarge)

Click Next to view Diagnosis and Discussion.


Mango Dermatitis

Both patients had eaten mangos 1-3 days prior to the onset of the rash.


Mango dermatitis usually results from contact with oleoresins in the rind during peeling or eating of the fruit.  It is of particular interest due to the frequency of cross sensitivity between mango and a number of other plant allergens.  

Mango belongs to the family Anacardiaceae.  The responsible allergen in mango dermatitis was named mangol, and was identified to be a group of alkenyl resourcinols.1  Resorcinols are the allergens of several other plant contactants. Cashew is another plant in the family Anacardiaceae. The primary allergen in cashew nut oil is known as cardol, which, like mangol, it is a resorcinol.  Another family of plants having allergens with related structures is the Gingkoaceae family.  The allergen in gingko nuts is known as bilobol, also a resorcinol.  

Contact allergy may also occur to other members of the Anacardiaceae family, including poison ivy/oak and the Japanese lacquer tree.  These plants are from the genus Toxicahedron, and contain the allergen, urushiol, which is composed of alkyl catechols.  Because the clinical structures of the  allergens belonging to the Anacardiaceae and the Gingkoaceae family are alkyl or alkenyl resorcinols and catechols, the alkyl/ alkenyl group might be recognized as an epitope, allowing both resorcinols and catechols to act as common allergens.3

Cross reactions amongst these plant allergens are common, and patients with allergy to catechols are almost always sensitive to resorcinols as well.   In a study of subjects with urushiol sensitivity from Japanese lacquer exposure, 5 of 6  reacted to one or more resorcinols in mangol.3  Similarly, all 28 patients with poison ivy dermatitis who were tested had positive patch tests using the cashew nut allergen cardol, a resorcinol.2  

However, those with allergy to resorcinols do not always react to catechols. Of 14 patients with mango dermatitis, only 50% reacted to urushiol, a catechol derivative, while all reacted to an extract of gingko, whose allergen, like mangol, is a resorcinol.1

Because of this high rate of cross sensitivity, patients with history of sensitization to poison ivy may develop mango dermatitis on their first exposure. In a recent report from Israel, mango dermatitis was reported in 17 of 32 Americans employed in mango picking at a summer camp, despite absence of a history of prior contact with mangos.4  Those who developed dermatitis lived in states where poison ivy/oak sensitization is common.  

None of 30 Israeli youths who also participated developed dermatitis.  It was speculated that this difference was related to the route of initial allergen exposure.  While the Americans had cutaneous exposure to poison ivy/oak resulting in sensitization, the initial Israeli exposure was more likely  through ingestion. This may have allowed antigen presentation to gut-associated lymphoid tissue resulting in the induction of specific immunological tolerance.

1. Saito F, Oka K, Kuzuhara M, Ikeda Y, Yoshimura K. Mango allergen - cross sensitivity between other plants and mango allergen. Jpn J Dermatoallergol 1994: 1: 266-273. (in Japanese. As referenced in 3.)

2. Keil H, Wasserman D, Dawson C R. The relation of hypersensitiveness to poison ivy and to the pure ingredients in cashew nut shell liquid and related substances. Industrial Med Surg 1945: 14: 825-830.

3. Oka K, Saito F, Yasuhara T, Sugimoto A. A study of cross-reactions between mango contact allergens and urushiol. Contact Dermatitis 2004 Nov-Dec;51(5-6):292-6.

4. Hershko K, Weinberg I, Ingber A. Exploring the mango-poison ivy connection: the riddle of discriminative plant dermatitis. Contact Dermatitis 2005 Jan;52(1):3-5.

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