Discussion
SJS is a rare adverse drug reaction with a high mortality rate and
multi- organ failure. This syndrome is characterized by dusty patches,
atypical targetoid lesions, bullae and erosions and epidermal detachment
less than 10%. It occurs more often in women unlike our case.
There are various mechanisms by which this syndrome occurs. First of
all, after the responsible drug is taken, the drug itself binds to
T-cell receptors or MHC class 1 receptors in antigen-presenting-cells
(APC). The result is clonal expansion of CD8+ cytotoxic T cells and
Natural Killer Cells (NK Cells); leading to epidermal necrosis.
Fas-FasL, expressed on the activated cytotoxic T cells, can also destroy
keratinocytes via the production of intracellular caspases. In addition,
it is thought that nitrous oxide (NO) induced by tumor necrosis factor-α
(TNF-α) and interferon (IFN)-alpha may also stimulate caspases.[1] Moreover, recent studies have shown high levels of
cytotoxic molecules within lesions of SJS/TEN, such as perforin,
granzyme B, and granulysin. [2]
SJS may be caused by either drugs or infections. The most frequently
associated drugs are reported as allopurinol, aminopenicillins,
cephalosporins, anticonvulsants and NSAIDs. [3] To our
knowledge, there is no reported SJS case caused by favipiravir, in the
literature. In our case; it is not clear whether the lesions of the
patient are caused by Covid-19 infection or by the use of favipiravir.
There are various skin manifestations of COVID-19 reported in the recent
literature. Those findings include urticaria, pityriasis rosea-like
eruption, chickenpox-like vesicles and chillblain-like lesions.[4] Moreover, SJS-like lesions may be a manifestation of
COVID-19 infection, as well. Up to now, there are a few case reports in
the literature indicating that Covid-19 disease may be related with SJS.
Parlakay et al. reported a case of a pediatric patient, with COVID-19
presenting like SJS. In their case, either amoxicillin-clavulonate
treatment given for tonsillitis or COVID-19 infection could be the cause
of SJS, as in our case. [5] In addition, it is discussed in
a case-report that viral infections such as COVID-19 might induce SJS
and susceptibility to drugs may be increased in patients with COVID-19
infection. [6] Despite the fact that, SJS has been linked
to drug exposure, infectious agents such as HIV , Mycoplasma
pneumonia , Herpes Simplex virus may have an effect on the
incidence of SJS. [2] In fact, there is still no evidence
that Covid-19 infection is a cause of SJS. We wanted to indicate that,
SJS - a very serious adverse drug reaction -may be triggered by either Covid-19 - the very common
disease all over the world - or by the very commonly used
drug, favipiravir.