Flagellate dermatitis after consumption of Shiitake mushrooms

Recognizing Flagellate Erythema in Skin of Color: A Case of Shiitake Dermatitis

Flagellate erythema, also known as flagellate dermatitis, flagellate hyperpigmentation, or shiitake dermatitis, is a rare multifocal cutaneous eruption characterized by linear erythematous lesions similar to flagellation wounds. This case report details the progressive onset of flagellate erythema in a 31-year-old African American male presenting with pruritic, erythematous, hyperpigmented, linear lesions of the face, trunk, and upper extremities following his consumption of shiitake mushrooms. Classically, this eruption arises subsequent to the ingestion of raw or undercooked shiitake mushrooms. This case underscores the importance of clinical diagnosis, as the role of biopsy as a diagnostic tool is limited due to the nonspecific nature of histological findings. Therefore, proper diagnosis is reliant upon careful history taking, including dietary changes, initiation of any new medications, and progression of symptoms. Most cases are self-limiting, with eruptions persisting for up to three weeks. Treatment aims to provide symptomatic relief through topical corticosteroids and oral antihistamines, reducing associated pruritus and skin changes.

Shiitake flagellate dermatitis (toxicoderma): A case report

We report a patient with flagellate dermatitis (shiitake dermatitis) appearing 48 hours after consumption of shiitake mushrooms in a previously healthy 37-year-old man. The skin lesion resolved completely within a week following treatment with antihistamine and topical steroid cream (dexamethasone 0.1%).

Flagellate Dermatitis by Shiitake Mushroom

The authors present a case of flagellate dermatitis in a previously healthy young male, triggered by the consumption of shiitake mushrooms. Complete remission without complications was obtained within 7 days, simply by the application of dexamethasone cream 0.1%. Considering the growing use of this originally Asian fungus in cookery worldwide, it is likely that we will see increased occurrence of this benign and self-limited condition also in the Western world.

Histological Features of Flagellate Erythema

Flagellate erythema is a distinctive eruption characterized by "whip-like" linear or curvilinear streaks and plaques, occurring mainly on the trunk. It has classically been described in 2 disparate clinical settings: chemotherapy with bleomycin and ingestion of mushrooms (most commonly Shiitake mushrooms). Most of the literature comprises single case reports, often with minimal histological description of rather nonspecific features. We describe in detail the histological features of 3 cases of flagellate erythema (2 related to bleomycin therapy and one related to ingestion of mushrooms) and review the findings described in the literature to define the spectrum of histological changes encountered in this eruption. Our 3 cases showed mild epidermal changes, with spongiosis and variable interface inflammation. All 3 showed a relatively prominent dermal lymphohistiocytic infiltrate, with features suggestive of a lymphocytic vasculopathy extending to at least the mid-reticular dermis. Eosinophils were a prominent component of the inflammatory infiltrate in 2 cases. Our review of the literature identified a total of 45 publications, representing reports of 46 patients, containing histological information. As well as bleomycin- and mushroom-related cases, similar eruptions have been reported in the context of connective tissue disease and other drugs. Although cases related to connective tissue disease show features of the underlying condition, cases secondary to drugs or mushrooms predominantly show features compatible with common patterns of exanthematous/morbilliform drug reaction. In particular, subtle spongiosis and/or interface dermatitis combined with a dermal lymphocytic infiltrate that includes increased numbers of eosinophils is a common finding. Features of a lymphocytic vasculopathy may be seen in a subset of these cases.

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.