The
allergens causing mango
dermatitis have long been suspected to be alk(en)yl
catechols and/or alk(en)yl
resorcinols on the basis of observed cross-sensitivity reactions to mango in patients known to be sensitive to poison ivy and oak (Toxicodendron spp.). Earlier, we reported the 3
resorcinol derivatives: heptadecadienylresorcinol (I), heptadecenylresorcinol (II) and pentadecylresorcinol (III); collectively named 'mangol', as mango
allergens. In this study, we extracted the 1st 2 components (I and II) from the Philippine mango, adjusted them to 0.05% concentration in
petrolatum and patch tested the components on 2 subjects with mango
dermatitis. Both subjects reacted to I. 1 subject also elicited a weaker positive reaction to II. To investigate the cross-reaction between mangol and
urushiol, we also patch tested the same subjects with
urushiol. The subject sensitive to II reacted to
urushiol. 6 subjects with a history of lacquer
contact dermatitis and positive reactions to
urushiol were similarly patch tested. 5 persons reacted to I. 2 subjects also exhibited a slower but positive reaction to II. This is the 1st report in which heptadec(adi)enyl
resorcinols known to be present in mango have been shown to elicit positive patch test reactions in mango-sensitive patients.