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Case report

In December 2004, a 69-year-old man came to the ENT unit of the University of Parma complaining of a painful cutaneous lesion in the left retroauricular region. The patient reported that the lesion appeared 4 weeks after a cochlear implantation procedure performed elsewhere 2 months before because of a bilateral profound deafness. The lesion was initially managed by his practitioner with oral and topical antibiotics in the suspicion of impetigo. Nevertheless, no benefits came after a 15-day antibiotic course. The patient’s medical history included diagnosis of oral pemphigus vulgaris (PV) 6 years before that was treated with oral azathioprine and topical clobetasol dipropionate ointment. After complete clinical remission of the disease, a low-dose immunosuppressive therapy was prescribed for the patient, which was stopped 1 month before cochlear implant surgery.

Clinical ear, nose, and throat examination documented 2 erosive areas located in the left retroauricular region along the surgical scar of the cochlear implant, extending several centimeters around it. No other similar lesions were documented on the rest of the skin; no erosive mucosal lesions of the nasal cavities, oral cavity, pharynx, and larynx were found on flexible fiber-optic endoscopy. No palpable neck masses were present, and complete blood cell count was normal.

Given the history of PV, a perilesional biopsy was performed in the suspicion of a reactivation of the disease. Histopathologic evaluation showed isolated basal keratinocytes in a “tombstone” fashion, suprabasal cleavage of the epidermis, and acantholytic cells. These clues were also evident in the follicular structure, which presented acantholysis of the outer root sheath epithelium. Indirect immunofluorescence demonstrated focal fluorescence between keratinocytes at a dilution of 1/80, thus confirming the diagnosis of PV. Results of hematologic investigations and total-body computed tomography scan, performed to reveal a possible paraneoplastic origin of PV, were all negative.

The patient was treated with oral methylprednisone, 1 mg/kg of body weight, and oral azathioprine, 150 mg/d, with rapid improvement of the lesion. Complete clinical resolution was reached in 5 weeks, and therapy was consequently tapered. After 12 months from treatment institution, the result of indirect immunofluorescence was negative; and the patient was well and free from PV under low-dose oral methylprednisone and azathioprine.

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Discussion

Pemphigus vulgaris is an autoimmune blistering disease caused by pathogenic autoantibodies directed against cadherin-type epithelial cell adhesion molecules, principally desmoglein 3 and 1, that are located in the extracellular domain of the desmosome. Although it is well known that oral PV lesions may often precede, even by many months, development of cutaneous lesions, we believe that, in this case, cutaneous PV is unrelated to the natural course of the disease. In our opinion, it may have been triggered by surgery itself, as an isomorphic response of Koebner.

Isomorphic response is a very common event in psoriasis, lichen planus, and vitiligo; but it has been reported less often in other types of dermatoses such as Darier disease, skin metastases, and pyoderma gangrenosum . The etiopathogenesis of such type of response is unclear and probably involves a multifactorial process. It may be induced by various physical stimuli, almost exclusively in a mono- or paucilesional presentation, limited to the site of trauma . Ultraviolet light exposure, x-ray irradiation, burns, electrosurgery, and, like in our case, traditional surgery have all been indicated as triggering factors. Among these, however, surgical manipulation represents one of the most commonly reported .

Notably, postsurgical PV may appear either as first episode or, in turn, as secondary presentation, like in the cased reported. It is in fact noteworthy that PV of the scalp appeared in the site of the surgical wound; and moreover, the time gap between surgery and PV was sufficiently short to hypothesize a “cause-effect” relationship.

A possible explanation to a higher susceptibility of scar tissue to pemphigus is that the scarring process may give rise to an abnormal differentiation of keratinocytes, which may secondarily lead to exposure of pemphigus antigens. Yet, discontinuance of immunosuppressive therapy before a traumatic injury (surgery) may have rendered the patient not able to fend off the reactivation. Consequently, the surgical site might be more prone to develop the disease, even in the presence of low titers of pemphigus autoantibodies .

To the best of our knowledge, reactivation of cutaneous diseases, and particularly PV, through the Koebner phenomenon after cochlear implantation has not been reported. Cochlear implant is widely used and usually well tolerated by both infants and adults. Surgical complications are mainly related to device failure and to scalp flap complications (eg, infection and necrosis) . Patients with autoimmune blistering diseases like PV should undergo adequate immunologic evaluation before surgery to discuss the possibility of an adequate immunosuppressive treatment plan. Moreover, the patients have to be forewarned about the possibility of cutaneous reactivation of the disease after surgical manipulations, even many months after the first presentation of a preceding mucocutaneous episode.