Shiitake dermatitis: a distinctive clinical entity

Shiitake dermatitis: experience of the Poison Control Centre Network in France from 2014 to 2019

OBJECTIVE

Shiitake mushrooms (Lentinus edodes) are an edible fungus, initially grown in Japan and China that are increasingly marketed in Europe. We previously presented 15 shiitake dermatitis cases reported to Poison Control Centres (PCCs) in France from January 2000 to December 2013. The aim of this study was to describe changes in the number of shiitake dermatitis cases since 2014, and to better describe the clinical characteristics and risk factors of this reaction.

CASE SERIES

This observational study is a retrospective review of cases in the French PCCs database between 1 January 2014 and 31 December 2019. Out of 125 shiitake exposures, we identified 59 cases of dermatitis: sex ratio of 1.80 M/F; ages ranging from 19 to 69 years (median: 39 years). Dermatitis occurred after raw or undercooked shiitake consumption (e.g., from the wok, in soup, or on pizza). The rash appeared 1-168 h (median: 48 h) after shiitake ingestion. Linear, erythematous, urticarial papules and plaques developed across the trunk, arms, and legs within a few hours and persisted for 1-40 d (median 10 d). The amount of shiitake eaten (low vs. medium vs. high) significantly increased the duration of dermatitis (median days 4 vs. 7 vs. 15, respectively; p = .007). In all, 38 patients received corticosteroids, antihistamine drugs, or both without demonstrated benefit. All patients made a complete recovery.

CONCLUSIONS

The mechanism of shiitake dermatitis is thought to involve lentinan, a heat-labile polysaccharide component. Inadequate cooking clearly seems to be a driver of the occurrence of shiitake dermatitis. This study highlighted a dose-dependent response, suggesting a partial toxic mechanism or a th1-type hypersensitivity mechanism. Treatment is focused on symptom management. Health professionals and the general population should be aware of both the risk associated with inadequately cooked shiitake consumption and the favourable prognosis of this still poorly known toxic dermatitis.

Shiitake Mushroom Dermatitis: A Review

Shiitake mushroom dermatitis is a cutaneous reaction caused by the consumption of raw or undercooked shiitake mushrooms. Symptoms include linear erythematous eruptions with papules, papulovesicles or plaques, and severe pruritus. It is likely caused by lentinan, a heat-inactivated beta-glucan polysaccharide. Cases were initially reported in Japan but have now been documented in other Asian countries, North America, South America, and Europe, as this mushroom is now cultivated and consumed worldwide. Shiitake mushroom dermatitis may result from mushroom ingestion or from handling, which can result in an allergic contact dermatitis.

Shiitake dermatitis recorded by French Poison Control Centers - new case series with clinical observations

CONTEXT

Shiitake (Lentinula edodes) is an edible mushroom which was initially grown in Japan and China and is now sold on the European market. Flagellate erythema may arise following shiitake consumption and was first described in Japan in 1974.

OBJECTIVE

This paper reports a French shiitake dermatitis case series.

METHODS

The findings of retrospective study of shiitake dermatitis cases, reported to French Poison Control Centres (PCC) from January 2000 to December 2013, are reported.

RESULTS

Among 32 exposed patients, 15 presented flagellate urticarial lesions after raw shiitake consumption. The first case of this series was reported in 2006 and the last nine cases were reported as of 2012. After shared meals, no symptoms were reported among guests, who preferred cooked shiitake to the raw mushroom. In this series, rashes appeared 12 h to 5 days (median: 24 h) after raw shiitake ingestion. Linear and itchy urticarial lesions formed on the trunk, arms, and legs within a few hours and persisted for 3-21 days. In four cases, rash and pruritus were either triggered or worsened by sun exposure. Eleven patients received corticosteroids, antihistamines, or both. All patients completely recovered.

CONCLUSION

Due to the rapidly increasing consumption of exotic food in Western countries, it is no surprise that cases of shiitake dermatitis are now appearing in Europe. The mechanism of shiitake dermatitis is thought to be toxic and due to lentinan, a polysaccharide component of the mushroom. There is no specific validated treatment for shiitake dermatitis. Health professionals and the general population should be aware of both the risk associated with raw shiitake consumption and of the good prognosis of this very spectacular and uncomfortable toxic dermatitis.