DR [Dermatology Reports 2011; 3:e21] [page 47] Flagellate dermatitis following consumption of shiitake mushroom Hui Voon Loo, Hazel H. Oon National Skin Centre, Singapore Abstract Japanese dermatologists were the first to describe the very characteristic flagellate der- matitis following consumption of under- cooked or raw shiitake mushroom (Lentinus edodes). These similar eruptions were also re- ported in patients treated with bleomycin, in dermatomyositis and adult onset Still’s dis- ease. We report a case where a 40 year old chi- nese female developed flagellate dermatitis following ingestion of a bun containing shi- itake mushroom. Introduction Flagellate literally means to whip (someone), either as a religious discipline or for sexual gratification according to Oxford Dictionary. Flagellate dermatitis or toxico- derma presents with very characteristic linear wheal like skin manifestations and is often as- sociated with shiitake mushroom (Lentinus edodes). It was first described by Nakamura in 1985.1 We report a 40 year old lady who devel- oped flagellate dermatitis following ingestion of a bun containing shiitake mushroom. Case Report A 40 year old lady complained of acute onset of unusual rashes on her neck, body and limbs for 2 days. She reported feeling itchy on her arms and kept scratching, but denied scratching her trunk. She denied taking any medications. Physical examination revealed extensive flagellate dermatitis on arms, trunk, legs, neck, forehead and some pinpoint pe- techiae on arms (Figure 1). On further ques- tioning, patient recalled eating portobello mushroom from an Italian restaurant 5 days ago and a mushroom bun from a bakery shop 3 days ago, but could not recall taking shiitake mushroom. She recalled having itch when she ate mushroom in the past but no rash. Her full blood counts, liver function tests, creatine kinase and creatinine were normal. Her ANA was a low titre at 1:100 (speckled). She received oral prednisolone and antihistamines. On further clarification with the bakery shop, the mushroom bun that she ate 3 days prior to the onset of rash contained shiitake mushroom. She was advised to avoid shiitake Mushroom in future. Her rash improved subsequently. Discussion Flagellate dermatitis typically presents with multiple intensely pruritic, erythematous linear plaques and papules on the trunk and extremities.2 Such cutaneous reactions often occurred 48 hours following ingestion of under-cooked or raw shiitake mushroom.3 The average duration of involvement was 8.5 days and improvement was generally noticed within 2 to 14 days.4 People involved in cultivating and mar- keting shiitake mushrooms may develop al- lergic alveolitis on inhalation of mushroom spores and contact dermatitis upon contact with the mushroom. They may have positive patch tests and specific IgE antibodies. However, in shiitake dermatitis, skin prick and patch tests were mostly negative except for a few cases re- port by Lipper.3 There was a suggestion of possi- bility of UVA photodermatosis by Hanada during which 47% of patients with shiitake dermatitis had reproducible skin lesions to UVA on pho- totesting but not with UVB.5 Histology findings are nonspecific. Acutely, the skin biopsy shows spongiosis, elongated rete ridges with infil- trates of degenerative epidermal cells, lympho- cytes, eosinophils and dermal oedema with perivascular infiltrates of lymphocytes, neu- trophils, and eosinophils.4 The exact underlying pathogenesis is still uncertain. Koebnerisation was postulated by Nakamura, although scratching did not repro- duce the eruptions.4 Lentinan, a polysaccha- ride found in shiitake has been implicated by a direct toxic effect, leading to interleukin-1 se- cretion, causing vasodilation, haemorrhage and the eruption.5 Heat may play a role in de- naturing the toxin as flagellate dermatitis mostly only occurs in patients who consumed the under-cooked mushroom.4 Flagellate dermatitis was also reported in patients treated with bleomycin, in dermato- myositis6 and HIV patients.7 In bleomycin-in- duced flagellate dermatitis, patients developed linear pruritic pigmented lesions between 1 day and 9 weeks after the administration and may recur upon rechallenge of the drug. It was reported to occur, in a dose dependent manner, in about 8 to 66% of patients treated with bleomycin. Some patients may develop such eruptions even with a very low dose of bleomycin.8 Three cases of AIDS patient with Kaposi’s sarcoma treated with relatively low dose of bleomycin were also reported to de- velop pruritic flagellate dermatitis.6 During the acute phase of bleomycin-induced flagellate dermatitis, the histological findings are sim- ilar to fixed drug eruption. This includes basal vaculolar alteration, pigmentary incontinence, dyskeratotic keratinocytes and perivascular dermal infiltrates of lymphocytes and eosinophils. Ultrastructurally, there is in- creased contact time between melanocytes and keratinocytes from the decrease in epidermal turnover, with the melanocytes being arrested in a pigment-producing state. Some authors suggested that since the skin lacks hydrolase which inactivates bleomycin, the local accu- mulation of bleomycin in skin could result in inflammatory reactions, similar to that of a fixed drug eruption. The hyperpigmentation may be postinflammatory rather than a pri- mary sign. Nevertheless, the dermatitis re- solves with cessation of bleomycin but hyper- pigmentation can persist up to eight months.9 Previously, it was thought that this was class specific to bleomycin. In 2007, there was a case report of a patient developing flagellate erythema after three days treatment with doc- etaxel for metastatic breast cancer. Her pruritus and erythema resolved spontaneously with res- olution of pigmentation gradually over weeks.10 Rarely, patients with dermatomyositis present with centripetal flagellate erythema on the trunk and proximal extremities. The histo- logical findings showed interface dermatitis. Such unusual eruptions have not been re- ported in other types of connective tissues dis- Dermatology Reports 2011; volume 3:e21 Correspondence: Hazel H. Oon, National Skin Centre 1, Mandalay Road, Singapore 308205. Tel. 65.62534455 - Fax: 65.62533225. E-mail: hazeloon@nsc.gov.sg Key words: flagellate dermatitis, shiitake mushroom, lentinan poisoning. This paper has not been published or submitted for publication elsewhere. All authors have contributed significantly and are in agreement with the content of the manuscript. Conflict of interest: the authors have no conflict of interest. There are no financial or personal relationship between the authors and others that could bias the work set out in the manuscript. Received for publication: 23 July 2011. Accepted for publication: 10 August 2011. This work is licensed under a Creative Commons Attribution NonCommercial 3.0 License (CC BY- NC 3.0). ©Copyright H.V. Oon et al., 2011 Licensee PAGEPress, Italy Dermatology Reports 2011; 3:e21 doi:10.4081/dr.2011.e21 No n- co mm er cia l u se on ly [page 48] [Dermatology Reports 2011; 3:e21] ease except for adult onset Still’s disease. The intensity of the flagellate dermatitis purport- edly mirrors the disease severity of dermato- myositis and may indicate a more complicated course of disease in adult onset Still’s dis- ease.6,11 Even less commonly, HIV patients with hypereosinophilic syndrome were also re- ported to present with unusual cutaneous manifestations of linear flagellate plaques.7 Conclusions Flagellate erythema was initially described in patients who consumed raw or undercooked shiitake mushroom. However, such eruptions are also characteristic of several diseases, each having their own distinguishing clinical features. Shiitake mushroom is the second most cultivated mushroom in the world and was reported to have immunomodulatory ef- fects.4 Perhaps a wise move would be to con- sume the thoroughly cooked mushroom so that this delicious delicacy could be savoured without adverse effects. References 1. Nakamura T, Kobayashi A. Toxicodermia cause by the edible mushroom shiitake (Lentinus edodes). Hautarzt 1985;36:591-3. 2. Arseculeratne G, Berroeta L, Meiklejohn D, et al. Bleomycin-induced flagellate der- matitis. Arch Dermatol 2007;143:1461-2. 3. Lippert U, Martin V, Schwertfeger C, et al. Shiitake dermatitis. Br J Dermatol 2003; 148:178-9. 4. Nakamura T. Shiitake (Lentinus edodes) dermatitis. Contact Dermatitis 1992;27: 65-70. 5. Hanada K, Hashimoto I. Flagellate mush- room (Shiitake) dermatitis and photosen- sitivity. Dermatology 1998;197:255-7. 6. Nousari HC, Ha VT, Laman SD, et al. Cen- tripetal flagellate erythema: a cutaneous manifestation associated with dermato- myositis. J Rheumatol 1999;26:692-5. 7. May LP, Kelly J, Sanchez M. Hypere- osinophilic syndrome with unusual cuta- neous manifestations in two men with HIV infection. J Am Acad Dermatol 1990;23 (2 Pt 1):202-4 8. Nandwania R, Money-Kyrle J, Hawkins DA, et al. Bleomycin-induced flagellate der- matitis in AIDS patients with Kaposi’s sar- coma. J Eur Acad Dermatol Venerol 1995; 4:89-95. 9. Vuerstaek J.D, Frank J, Poblete-Gutiérrez P. Bleomycin-induced flagellate dermatitis. Intern J of Dermatol 2007;46:3-5. 10. Tallon B, Lamb S. Flagellate erythema in- duced by docetaxel. Clin Exp Dermatol 2007;33:276-7. 11. Yamamoto T, Nishioka K. Flagellate ery- thema. Int J Dermatol 2006;45:627-31. Case Report Table 1. Characteristics of flagellate erythema found in different conditions. Shiitake flagellate Bleomycin-induced Dermatomyositis Adult onset Still’s disease HIV associated dermatitis flagellate erythema associated flagellate associated flagellate flagellate erythema4 erythema erythema10 Clinical features 1. Pruritic erythematous 1. Hyperpigmented brownish 1. Centripetal reddish linear 1. Persistent plaques with 1. Linear flagellate plaques linear papules, sparing linear streaks streaks with erythematous linear pigmentation with accompanying fever the inaccessible areas 2. Occurs 1 day to 9 weeks plaques or without coalescent and eosinophilia to scratching on the back post administration 2. Mirrors the disease erythematous plaques 2. HIV patients with 2. Triggered by of bleomycin in a severity 2. Presence could indicate hypereosinophilic under-cooked/raw Shiitake dose-dependant manner 3. Pruritus present, a worse prognosis with syndrome mushroom, commonly 48 hrs 3. Pruritus maybe absent, usually no pigmentation increased risk of systemic after ingestion pigmentation present complications and longer 3. Intense pruritus, time to remission usually no pigmentation 3. Pruritus and pigmentation may be present Histology Non-specific Similar to fixed drug eruption Interface dermatitis Dyskeratotic cells in the Mixed perivascular infiltrate (spongiosis, elongated rete in the acute phase epidermis and dermal with eosinophils, ridges, eosinophils Post-inflammatory infiltrates of neutrophils histiocytes, lymphocytes and lymphocytes infiltrates, hyperpigmentation in late and eosinophils dermal oedema) lesions Presence of flame bodies Treatment Topical and oral Discontinue bleomycin Topical /oral corticosteroids Main aim is to treat the Oral and topical corticosteroids, Short course of oral/ potent and immunosuppresants underlying systemic disease corticosteroids, antihistamines topical corticosteroids (topical calcineurin inhibitors, Oral corticosteroids and PUVA Self-limiting Self-limiting hydroxychloroquine) immunosuppressants Thoroughly cooked Shiitake Responds well to (methothrexate, cyclosporin) for future consumption conventional therapy May persist even after fever has subsided Figure 1. Linear grouped erythematous papules on lower limbs (a) and abdomen (b). a b No n- co mm er cia l u se on ly