Stevens-Johnson syndrome (SJS) was described for the first time in 1922 by Stevens and Johnson, who defined it as ‘a new kind of fever with skin eruptions and stomatitis’ (1). The disease is recognised as a severe drug-induced reaction, more rarely occurring as the consequence of infectious disease – the herpes simplex viruses type 1 and type 2, varicella zoster virus, cytomegalovirus infection, Epstein-Barr virus, type 6 and 7 herpes viruses, parvoviruses and Mycoplasma pneumoniae bacteria (2, 3). SJS prevalence is 1.2-6 cases per one million of people within a year, mainly referring to persons over 40 years of age. Numerous studies showed the relationship between SJS and over 200 various medicines. Individual groups of medicines were distinguished, the administration of which is subject to an increased risk. These are the following: sulphonamides (co-trimoxazole), anticonvulsants (carbamazepine, lamotrigine, phenytoin, phenobarbital), non-steroid anti-inflammatory medicines from the oxicam group, as well as nevirapine and allopurinol (2). The relationship between the episode and medicine intake is suggested by the fact that a new drug has been administered between 1^st and 8^th weeks before the occurrence of skin lesions. The average time between drug administration and occurrence of SJS symptoms was estimated as between 6 days and 2 weeks (2). Stevens-Johnson syndrome is a reaction induced by medicines, which activate cytotoxic T lymphocytes that trigger numerous factors responsible for keratinocyte apoptosis. Among the factors most frequently listed by researchers there are: granulysin, the high concentration of which may be found in the liquid inside blisters, perforin, granzyme B and Fas ligand (4). Infectious aetiology may be suspected when infection preceded the occurrence of skin lesions by one week and/or the titre of antibodies in IgM class may be determined, and in case of viral infection, its occurrence is confirmed with the use of a PCR test. At present, the disease is diagnosed when 10% of body surface is covered (3). Clinical symptoms involve sudden onset, high fever, malaise, joint pain and occurrence of skin eruptions in the form of blisters located on the skin, mucous membranes in the oral cavity, nose, sexual organs and conjunctiva. The blisters have poorly tight cover, easily rupturable, hence the clinical image may be dominated by erosions covered with haemorrhagic scabs. Sometimes lining in finger nails can be observed (3, 5). According to various researchers, the mortality rate of SJS oscillates between 2 and 7.5% (2). So far, no consensus has been reached as to the way of treatment of SJS. The core of treatment is early diagnosis and discontinuation of the agent causing the disease, then implementing both symptomatic and causal therapy. The symptomatic therapy involves fluid therapy, painkillers and antipyretic drugs. Glucocorticosteroids and antihistamine drugs are applied in causal therapy, and – in case of infectious aetiology – antibiotics and acyclovir. Local treatment of skin lesions involve application of swabs or creams with antibacterial agents, ointments or steroid creams, as well as biological or biosynthetic dressings (3). Average duration of the disease: 3-6 weeks. Patients with history indicating SJS should avoid using preparations included in the group of high-risk drugs (2, 5, 6).

The notion of ‘toxic epidermal necrolysis’ was suggested in 1956 by Lyell, when he observed ‘toxic skin lesions, resembling burns’ in some of his patients. Hence, the disease was also called the Lyell syndrome (7). The majority of authors treat the disease entity as more severe form of the Stevens-Johnson syndrome, with the borderline between them marked by the degree of epidermis lining. Accordingly, TEN is diagnosed when the disease covers > 30% of body surface. In case of lesions covering between 10 and 30% of body surface, the SJS-TEN overlapping syndrome is diagnosed (2). Consequently, toxic epidermal necrolysis is also included to the group of very severe drug-induces disorders, with symptoms of multi-organ insufficiency. The disease prevalence is estimated as 0.4-1.9 cases per million people per annum (2, 8). The mortality rate is 20-50% (4). The etiopathogenesis of toxic epidermal necrolysis is the same as that of the Stevens-Johnson syndrome (2). It is also related to the application of high-risk medicines (sulphonamides, anti-epileptic drugs, non-steroid anti-inflammatory medicines) and to bacterial and viral infections (3). Extensive and rapidly expanding epidermal necrosis is, similarly as SJS, the effect of cytotoxic T lymphocyte activation. Mediators responsible for epidermal necrosis include mainly granulysin, as well as ligand Fas, granzyme B and ligand inducing apoptosis linked to TNF (8). The difference between TEN and SJS is determined by the severity of clinical image of the patient and the possibility of occurrence of more serious complications (2). The initial, so-called prodromal period involves high fever, apathy, eye itching, catarrh and pharyngitis, occurring usually 1-10 days before the occurrence of basic symptoms. Then, there occurs the full-blown period, characterised by erythema on the face and trunk. Next, there occur blisters filled with serous liquid, which are subsequently exfoliated, leaving behind bleeding erosions, covered with scabs in the ultimate period. There occurs the Nikolsky sign, consisting in epidermal lining of the apparently healthy skin during its rubbing. The lesions also involve mucous membranes, initially as oedema, and then self-rupturing formed blisters, transforming into bloody erosions covered with grey quasi-membranes (3, 5, 8). The process covers the respiratory system in 30%. Lesions are also visible on mucous membranes of the digestive tract and urogenital system. If no immediate assistance is provided, the next stage involves occurrence of such complications as loss of liquids, with subsequent dyselectrolitemia and renal insufficiency, secondary bacterial infections complicated by sepsis, adhesions of mucous membranes (stenosis of anus, urethra, vagina), ulcerations of cornea, conjunctiva, adhesions of eyelids and even blindness (3, 6). In case of proper treatment, the period of treatment and recovery lasts several weeks. Distant complications are diagnosed in 29% of cases and these mainly involve: skin discolorations, scars, dry conjunctivitis, photophobia, deformations of nails and others (3). Patients with TEN should be treated at the intensive medical care unit or burn treatment ward. The core therapy involves discontinuation of the suspicious medicine, which considerably improves the prognosis. Disease severity is evaluated with the use of SCORTEN scale. It consists of 7 clinical and laboratory ratios. Each rate equals 1 score. According to the said scale, the mortality rate increases from 3.2% for 0-1 score to > 90% for > 5 scores (2). In order to accelerate elimination of the suspicious drug from the circulatory system, high doses of N-acetylcysteine are sometimes administered (2). The most frequently applied therapies involve mainly glucocorticoids, immunoglobulines and cyclosporin A (8). Though glucocorticoids show immunosuppressive effect, they inhibit the activity of cytotoxic T lymphocytes and they have been mainly used in high doses during initial periods of the disease, the current British guidelines do not recommend their application due to the involved higher risk of infections, longer hospitalisation time and increased mortality rates (9). Intravenously administered immunoglobulins became the most recognised therapy in TEN. The immunoglobulins suppress keratinocyte apoptosis through Fas receptors inhibition (9). European guidelines suggest they may be used during the initial stage of the disease, though they are reported to be ineffective (10). Cyclosporin A is another immunosuppressive drug used in TEN therapy. Its administration is attributed to faster healing of the epidermis. Basing on French studies, the accepted dose of cyclosporin A amounts to 3 mg/kg of body weight for 7 days. After that period, the dose should be reduced (9, 11). It is suggested that TNF alpha inhibitors may serve as an important treatment agent. Infliximab used in a single dose of 5 mg/kg proved effective, quickly improving skin lesions. Etanercept, another TNF alpha inhibitor, in a single dose, also makes the epidermis regeneration faster, while not causing deaths, despite the initially estimated mortality rate of 50%. On the other hand, thalidomide turned out to be detrimental, since it paradoxically increased the mortality rate (2, 8, 9). Summing up, the pharmacological procedure is still controversial, because there are not enough randomised studies. The basis for therapy is normovolaemia, efficient analgesia and counteracting infections.