BD is an extremely rare disease in Europe, especially in Poland. However, we diagnosed it in our patient, and it is possible that also other members of his family who had died from cardiovascular complications also suffered from BD. To the best of our knowledge, only two cases of BD in a Polish patient have been described [10, 11].

There is no single test that can confirm the diagnosis of BD [2]. It is made based on the clinical picture and simple exclusion of other diseases [7]. Diagnostic criteria for BD have been described. A main one that has to be met is recurrent oral ulcerations (at least three times a year), and there are others of which at least two have to be met: recurrent genital ulcerations (leaving scars), ocular lesions (anterior uveitis, posterior uveitis, presence of cells in the vitreous detected in the slit-lamp examination, retinal vasculitis), cutaneous lesions (erythema nodosum, pseudofolliculitis or papulopustular lesions, acneiform nodules in patients after adolescence and who are not using glucocorticoids) or positive pathergy test results with reading performed 24–48 h after the test [4]. In our patient we observed the main criterium as well as genital ulcerations, acne-like lesions and the pathergy phenomenon. Laboratory investigations in BD can reveal elevated levels of inflammatory markers such as CRP (C-reactive protein), erythrocyte sedimentation rate, white blood cells and serum inflammatory cytokines. Anemia due to chronic disease can also be noted. What is not typically observed in BD are antinuclear antibodies (ANA), rheumatoid factor (RF) and antineutrophil cytoplasmic antibodies (ANCA) [7]. Indeed, in the described case, ANA, ANCA and RF stayed within normal limits. Imaging tests can be helpful but due to the broad range of manifestations of BD, they should be adjusted to the presented symptoms.

As mentioned, BD can involve many bodily organs and systems. The most common first manifestation of this disease is lesions in the oral cavity, whereas the most common manifestation in general is genital lesions. The mentioned skin and mucosal symptoms are both recurrent painful erosions and ulcerations [7]. Other dermatologic disorders can be acne-like, folliculitis-like or erythema nodosum. Oral aphthae should be differentiated from conventional aphthae, recurrent aphthae stomatitis, pemphigus vulgaris, herpes simplex, deep fungal infections, syphilis and trauma-related lesions [12, 13]. Genital ulcerations should be differentiated from syphilis, herpes simplex, chancroid, lymphogranuloma venereum and sexual trauma [14]. Acne-like lesions in BD are slightly different from classic acne vulgaris since they involve sterile pustules and comedones are usually absent: the lesions frequently occur on the trunk, buttocks and extremities [4, 12]. As for erythema nodosum in BD, the microscopic picture of the skin sample may help to distinguish it from the classic erythema because of the presence of vasculitis [4]. Skin ulceration should be distinguished from pyoderma gangrenosum—probably the most famous disease associated with the pathergy phenomenon [15]. Joint involvement manifests as painful inflammation usually of the knee, ankle, elbow or wrist joints, but with no erosions or deformation. Ocular complications usually appear a few years after skin symptoms and can be diverse, even leading to blindness. BD can also affect the gastrointestinal, cardiovascular and nervous systems. Intestinal mucosal erosions can be present as well as vomiting and diarrhea—these were not observed in our patient. Cardiovascular manifestations may be superficial or include deep thrombophlebitis, cardiomyositis and pericarditis or—as in our patient’s mother, and possibly also other family members, but not in the patient—aneurysms. The most common neurologic symptom in BD is headaches, and in the described case they had persisted for many years [7]. Headaches in BD are usually the primary type, especially migraines and tension type. Among secondary headaches, the most frequent is due to cerebral venous thrombosis and the second to parenchymal abnormalities [16]. The characteristics of our patient’s headaches were not precisely established because of his mental disability but small focal lesions in the white matter of the brain were found, which could suggest the parenchymal type of neurologic BD manifestation. Psychotic episodes can also appear in BD, and in our patient one occurred after the first hospitalization [7]. In general, our patient would have obtained a good prognosis, since he presented with oral, genital and cutaneous lesions with no other systems involved, except for the nervous system disturbances.

The pathergy phenomenon is observed with different frequencies depending on the ethnicity of the patient. It is usually observed in individuals from areas of high BD prevalence and is estimated to be positive in about 70% of cases [2]. It manifests as the appearance of skin lesions at the site of a minor or non-severe trauma [7]. It was also observed in our patient, especially in the area that was compressed by too tight underwear (Fig. 3a).

There is no causal therapy for BD. Treatment depends on the clinical manifestation, severity of symptoms, age, gender and possible contraindications to particular drugs [4, 17]. Various medicines are proposed, usually anti-inflammatory and immunosupressive agents: glucocorticoids, colchicine, cyclosporin A, azathioprine, dapsone, mycophenolate mofetil or cyclophosphamide [4]. Another promising group of drugs is biologics, such as tumor necrosis factor (TNF) alfa inhibitors and interferon (INF) alfa [4]. According to the literature, anti-TNF alfa agents may be beneficial in BD with ocular, vascular, neurologic and gastrointestinal involvement in cases that are refractory to standard immunosuppressive drugs. IL-1 and IL-6 blocking agents may be effective in ocular and neurologic manifestations. Also, apremilast, a phosphodiesterase 4 inhibitor, can be considered for oral and genital ulcerations. INF alfa is used in uveitis and neurologic symptoms [18]. Moreover, topical medicines play an important role in managing symptoms, mainly skin and mucosal manifestations. These are topical glucocorticoids, antibiotics and antiseptics [17]. Lastly, there is concern about whether to administer anticoagulants or not, considering the vascular complications [17].

Behçet’s disease is very uncommon in locations other than Asia and along the Silk Road. The fact that there have only been a few cases of BD in Polish patients leads to lower awareness, and it is often not considered in the differential diagnosis. People’s migrations around the world may contribute to the more frequent occurrence of BD in Poland and Europe. The diversity of symptoms also causes difficulties in matching all of the signs that the patient presents and tracking the disease. The various manifestations of BD also lead to a broad spectrum of additional tests being carried out and multispecialty consultations with an interdisciplinary approach to the patient with medical surveillance.