A crop of mango dermatitis in the Northern Territory

To the Editor: Mango sap is released from broken stems and branches of mango trees. It contains substances that are thought to elicit a T cell-mediated response (urushiol, cardol, limonene and β-pinene).1 The response occurs over days and results in severe inflammation and blistering; the blistering can last weeks, similar to that produced by other plants in the Anachardiaceae family (poison oak, poison ivy, etc). The flesh and skin of the mango fruit can also cause a more typical type 1 hypersensitivity reaction.2

One in four Australian grown mangoes are from the Katherine region. During the 2012 mango harvest, 66 patients (82 presentations) attended Katherine Hospital emergency department with mango dermatitis or related complications over a 35-day period, and a further 31 people presented to a general practice clinic in Katherine. The majority of these patients (59/66) were workers from overseas, and English was not the first language for half of them (32/66). A wide range of nationalities was represented — the home countries of the patients ranged from Estonia to Fiji.

The highest number of emergency department presentations in 1 day was 17, a significant addition to the daily average of 47 emergency department presentations.

One patient was referred to Royal Darwin Hospital and underwent surgical debridement for severe extensive blistering. Two patients were admitted to Katherine Hospital with secondary cellulitis; one of them underwent surgical debridement of leg abscesses and was admitted for 8 days. One patient had throat swelling and one developed shingles after taking oral steroids — the main treatment specified for moderate and severe cases as per the hospital guideline.

In contrast to findings from a previous report,3 our experience suggests that prior sensitisation by exposure to Anachardiaceae plants is not required because most of the patients were transient tourist workers and thus first-time mango pickers. They are therefore unlikely to have had previous exposure.

Mango dermatitis can mostly be prevented by use of splash-proof clothing and gloves. During this surge of mango dermatitis, Katherine Hospital released a statement to the local media and mango industry. The 2013 season did not yield the same level of presentations.

Our experience highlights the non-benign nature of mango dermatitis and the public health role of all medical practitioners. Prompt communication with industry and workplace safety agencies can reduce morbidity and local health care burden.