Dermatologica Sinica

CORRESPONDENCE
Year
: 2021  |  Volume : 39  |  Issue : 3  |  Page : 159--160

Radiation-induced bullous pemphigoid in a patient with Kaposi's sarcoma


Jia-Di Lin, Sung-Jen Hung 
 Department of Dermatology, Buddhist Tzu-Chi General Hospital and Tzu-Chi University, Hualien, Taiwan

Correspondence Address:
Dr. Sung-Jen Hung
No. 707, Sec. 3, Chung-Yang Rd., Hualien
Taiwan




How to cite this article:
Lin JD, Hung SJ. Radiation-induced bullous pemphigoid in a patient with Kaposi's sarcoma.Dermatol Sin 2021;39:159-160


How to cite this URL:
Lin JD, Hung SJ. Radiation-induced bullous pemphigoid in a patient with Kaposi's sarcoma. Dermatol Sin [serial online] 2021 [cited 2021 Dec 5 ];39:159-160
Available from: https://www.dermsinica.org/text.asp?2021/39/3/159/326266


Full Text



Dear Editor,

Bullous pemphigoid (BP) is an autoimmune, subepidermal blistering disease characterized by autoantibodies against hemidesmosomal proteins. While typical BP presents as generalized tense bullae over trunk and extremities, radiation-induced BP often manifests as localized bullae at an area associated with prior radiotherapy.[1],[2] Herein, we report a case of radiation-induced BP in a patient with Kaposi's sarcoma successfully treated with lower dose systemic steroids and doxycycline.

An 82-year-old man with a history of classic Kaposi's sarcoma stage II in the right ankle and heel presented with multiple tense blisters over the right foot and posterior thigh for 3 days [Figure 1]a and [Figure 1]b. He received radiotherapy for Kaposi's sarcoma 1 week ago over the right ankle and foot. Those tense blisters developed over a radiated site (right foot) and a nearby nonradiated site (right posterior thigh) after four sessions of radiation therapy with a cumulative dose of 12 grays (Gy). There was no mucosal involvement. Skin biopsy over the right posterior thigh revealed subepidermal blisters with mixed eosinophils and lymphocytes [Figure 1]c. Direct immunofluorescence (DIF) showed linear IgG and C3 along the dermo-epidermal junction [Figure 1]d and [Figure 1]e. Blood tests showed elevated eosinophil count (Eosinophil count: 1,740/μL) and Ig E level (Ig E >5000 U/mL). In DIF detected a high titer (1:80) of circulating anti-basement membrane zone antibody. The diagnosis was radiation-induced BP.{Figure 1}

The patient was treated with oral prednisolone 20 mg/day (equal to 0.36 mg/kg/day) for 1 month. He received a total radiation dosage of 33 Gy for Kaposi's sarcoma. Prednisolone was slowly tapered within 3 months after the bullous lesions subsided. We utilized doxycycline 100 mg twice a day as a steroid-sparing agent. The patient received a second course of radiotherapy (30 Gy total) over the right inner thigh 3 months later for progressive Kaposi's sarcoma lesions. Recurrent tense bullae were observed over the radiation site during the radiotherapy [cumulative dosage: 20 Gy, Figure 1]f. Oral doxycycline was used for 1 year. The bullous lesions subsided 1 month later after completing radiotherapy. Bullous lesions showed no recurrence during 2-year follow-up.

Radiation-associated BP was a rare manifestation of radiation dermatitis,[1] with only 36 cases reported previously, including our patient. Thirty-one cases were women, of which 24 were being treated for breast cancer. The five males, including our patient, had associated lung cancer, esophageal cancer, metastatic squamous cell carcinoma, metastatic melanoma, and Kaposi's sarcoma.[2],[3],[4],[5],[6] Our patient was the only case of radiation-induced BP with Kaposi's sarcoma.

In our case, BP was diagnosed based on clinical features, histopathology, and immunofluorescence. The radiation-induced BP is different from idiopathic BP due to localized distribution over the radiation sites triggered by radiotherapy, compared to idiopathic BP with generalized distributions. Nearly 92% of patients presented with localized lesions at the radiation site [Table 1].[2],[3],[4],[5],[6] Majority (75%, 27 patients) had onset of BP after radiation therapy. One-quarter of patients (nine patients, including our case) had BP onset during the radiation therapy, with a mean dose of 25 Gy at the onset.[2],[3],[4],[5],[6] While the median radiation dose in radiation-induced BP was 50 Gy in previous cases,[1] our patient had received only 12 Gy at BP onset.{Table 1}

The mechanism of radiation-induced BP remains unknown. Some investigators proposed that radiation could cause apoptosis of epidermal cells, causing the release of BP antigens (BPAg1 and BPAg2), which are then processed by radiation-resistant Langerhans cells to present to T cells, and activate B cells to produce specific autoantibodies to BP antigen.[2] The role of different cancer types in radiation-induced BP could not be explained reasonably. Most cases of radiation-induced BP occurred predominantly in women with breast cancer. Some investigators proposed that breast epithelium (both luminal and myoepithelial cells) also express autoantigens of hemidesmosomes and release them after radiotherapy.[2]

The prognosis of radiation-induced BP is better than idiopathic BP. Most patients with radiation-induced BP had a low recurrence rate and good response to treatment with niacinamide, systemic, or topical steroid [Table 1].[2],[3],[4],[5],[6],[7] According to the previous clinical trials, doxycycline is the safer steroid-sparing agent but less effective than prednisolone for treating idiopathic BP.[8] The use of doxycycline to treat radiation-induced BP has not been reported before. Our patient was treated with doxycycline only during a recurrent episode of radiation-induced BP. In summary, we reported a case of radiation-induced BP in a patient with Kaposi's sarcoma, successfully treated with low-dose systemic steroids and doxycycline.

Declaration of patient consent

The authors certify that they have obtained appropriate patient consent form. In the form, the patient has given his consent for the images and other clinical information to be reported in the journal. The patient understands that his name and initial will not be published and due efforts will be made to conceal the identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

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