A 64-year-old woman presented with left axillary lymphadenopathy in December 2014. Metastatic infiltrating ductal carcinoma of the left breast and left axillary and pectoral lymph nodes was diagnosed. The tumor was clinical stage III T2N2, estrogen receptor negative, progesterone receptor negative, and HER2 overexpressed.\nShe began treatment in 2015 with triple therapy on February 24, March 17, and April 7: paclitaxel, pertuzumab, and trastuzumab. She also received monotherapy with paclitaxel on March 3, March 10, March 24, and March 31. Following her treatment on April 7, she developed eyelid ptosis and peripheral neuropathy with ataxia that was attributed to paclitaxel.\nMonotherapy with trastuzumab was resumed on May 9, 2015. On June 1, 2015, 3 days after receiving trastuzumab on May 29, 2015, she developed pruritus. She also noted a rash developing on her chest, abdomen, arms, and legs.\nCutaneous examination on June 3, 2015 showed erythematous, distinct and intermingled (in a lacy pattern), linear streaks on her arms (Figs. , ), chest, and abdomen (Fig. ). The morphology of the clinical lesions was a flagellate erythema. Similar linear streaks—both erythematous and hemorrhagic—were also noted on her legs (Figs. , ).\nA skin biopsy from her left arm showed basket-weave orthokeratosis overlying a spongiotic epidermis. There was edema in the dermis with a predominantly lymphocytic inflammatory infiltrate that is present around blood vessels in the papillary dermis. There was exocytosis of small lymphocytes into the overlying epidermis (Fig. ). The pathologic findings were those of a spongiotic dermatitis, compatible with a medication reaction.\nCorrelation of the clinical history, symptoms and findings in concert with the pathologic features observed established the diagnosis of drug-induced flagellate erythema. In this patient, the causative agent was trastuzumab.\nShe was treated systemically with prednisone (60 mg each morning for 3 days, followed by 40 mg each morning for 2 days and 20 mg in the morning for 1 day), and antihistamines for 2 weeks: Fexofenadine 180 mg each morning and diphenhydramine 25 mg each evening. Topical therapy was also initiated: Clobetasol propionate 0.05 % cream twice daily for 10 days and then once daily for 4 days.\nWithin 2 days, the itching had resolved and the skin eruption had nearly cleared. Follow-up examination after 2 weeks, on June 17, 2015, showed complete clearing of the flagellate erythema on her chest, abdomen, and arms. The erythematous hemorrhagic linear streaks on her distal legs were less prominent and asymptomatic.\nThe patient has subsequently had a left breast lumpectomy and complete lymph node dissection. There was no residual carcinoma in the breast and 26 lymph nodes were negative for malignancy. She has also received adjuvant radiation therapy.\nHer oncologist decided that she would need to receive treatment with trastuzumab, every 3 weeks, for 1 year. She has been receiving dexamethasone prior to each trastuzumab treatment to prevent recurrence of the adverse skin event. Neither pruritus nor flagellate erythema has occurred with the subsequent administration of trastuzumab.
Male patient, 30 years old, white, born and living in Rio de Janeiro, RJ, Brazil,\ncomplained of intense pruritus followed by disseminated erythematous lesions with onset\nless than 24 hours before. He had no history of associated diseases, use of any\nmedications or any other associated factors. On the first inspection we noted small\nerythematous papules and some petechiae that assumed a linear pattern located on the\ntrunk, lower and upper limbs. There were no mucosal abnormalities, fever or any other\nsystemic symptoms ( and ). Based on the peculiar rash, the patient was\nquestioned about the ingestion of shiitake and confirmed he had eaten a\nlarge amount of raw mushrooms five hours before the cutaneous lesions appeared, leading\nus to the diagnosis of flagellate erythema due to shiitake\ningestion.