PG is rare and some cases have been treated with HBOT;
7,8 however, no case of PG associated with UC has received such treatment. To the best of our knowledge, this is the first case of PG associated with UC that was successfully treated with HBOT. In our case, the patient first presented to a local clinic. Because of the ulcerative lesions that were not resolved despite antibiotic therapy and daily dressing, the patient visited our dermatologist who diagnosed PG without performing a biopsy examination. PG has no pathognomonic, pathologic, or histologic findings and, occasionally, a biopsy is performed to distinguish PG from infection, malignancy, vasculitis, and insect bites. However, diagnosis of PG is based on the clinician's experience and the patient's clinical manifestations.
9,10 In the present case, the anatomical location (shins) of the lesion, the findings of the dermatologist, the patient's underlying UC, a lack of abnormal lesion on CT angiography, and the clinical course supported the diagnosis of PG. Therefore, we concluded that the clinical diagnosis was PG associated with UC. Nevertheless, it is possible that this case of PG was idiopathic PG. Although up to 50% of PG cases are idiopathic, the remaining cases seem to be associated with other conditions, with IBD being one of the most common associated diseases.
11 Even though most cases of PG associated with UC develop with exacerbation of bowel disease, PG is not closely related to the activity of colitis and can develop after colectomy.
1,12,13 These facts support our diagnosis. While the pathogenesis of PG is poorly understood, neutrophil dysfunction, disturbance of immune system regulation, and genetic predisposition have been proposed as possible pathogenic mechanisms.
11 Many reports have revealed the use of various treatments based on clinical experience.
9 Recently, anti-TNF agents have been suggested as treatment options for PG associated with UC.
2,3,4,9,10,11,14 According to previous reports, the treatment success rate is high and the response is rapid. However, it is unclear when the anti-TNF agent is to be discontinued and, although rare, adverse effects, such as respiratory infection or lymphoma, must be considered.
Use of HBOT for wound healing is well known. HBOT is performed in a closed hyperbaric chamber with 100% oxygen at 2 to 3 atmospheres. HBOT improves the local hypoxia of wounds by increasing the amount of oxygen dissolved in the blood. HBOT has some bactericidal effects, inhibits vasoconstriction, and improves angiogenesis. These actions may enhance wound healing and tissue regeneration. In general, the duration of a single treatment varies from 45 to 120 minutes at 2 to 3 atmospheres. Although some adverse effects may occur with HBOT, such as reversible myopia, claustrophobia, and equalization problems due to pressure differences in either or both ears, most are reversible or self-limiting. In general, HBOT is considered to be a very safe modality when used according to standard protocols.
15
Cases of PG treated with HBOT have been previously reported. However, to the best of our knowledge, this is the first report of PG associated with UC that was treated with HBOT. Thus, this is the first case to highlight the possibility of HBOT as a safe and effective treatment choice for PG associated with UC, especially in patients who do not require anti-TNF agents. Moreover, HBOT precludes any concern about the adverse effects of anti-TNF agents.