While the genetics of SLE are not very well understood, there is growing evidence for the involvement of specific genes in this complex autoimmune disease . Part of the complexity of this disease is due to the effects of both environment and genetics factors that may contribute to its development.  Further compounding our understanding of the etiology of the disease is the involvement of several organ systems.  Genetic studies of the rates of disease in families supports the genetic basis of this disease with a heritability of >66%.  Identical ( monozygotic ) twins were found to share susceptibility to the disease at >35% rate compared to fraternal ( dizygotic ) twins and other full siblings who only showed a 2–5% concordance in shared inheritance. 
It seems strange, then, that allergic reactions to corticosteroids actually occur—especially since these medications are used to treat allergic reactions. While severe allergic reactions to corticosteroids are extremely rare, they do in fact occur. Most allergic reactions to corticosteroids are less severe, however, and result from the topical formulations—occurring in up to 6% of people. Allergic reactions to oral or injected formulations are rarer, occurring in less than 1% of people. Causes of allergic reactions to corticosteroids may be due to IgE antibodies , or as a result of delayed-type hypersensitivity reactions caused by T-cells (a type of white blood cell).