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.
The patient was a previously healthy 23-year-old Caucasian male who complained of the sudden onset of linear rash on his trunk evolving for 2 days. The patient denied other symptoms, such as pruritus, arthralgia, mucosal abnormalities, and fever. When asked about consumption of shiitake, he confirmed that he had eaten those mushrooms 4 days before he sought medical assistance and stated that he thought the shiitakes had been well cooked. The patient denied the intake of other medications or changes of personal hygiene products.\nAt physical examination, the patient presented with small, grouped papules forming a linear design, spreading on the trunk and extending to the proximal part of the upper limbs (Fig. , , ). No alterations on the face, scalp, or mucosa were observed. Dexamethasone ointment was applied for 5 days in the area of the lesions, and complete remission was observed after 7 days.