Resolution within 7–10 days is the norm. Individuals with persistent (chronic) erythema multiforme will often have a lesion form at an injury site, e.g. a minor scratch or abrasion, within a week. Irritation or even pressure from clothing will cause the erythema sore to continue to expand along its margins for weeks or months, long after the original sore at the center heals. Causes
Many suspected etiologic factors have been reported to cause EM. Infections: bacterial (including Bacillus Calmette–Guérin (BCG) vaccination, haemolytic Streptococci, legionellosis, leprosy, Neisseria meningitidis, Mycobacterium, Pneumococcus, Salmonella species, Staphylococcus species, Mycoplasma pneumoniae), chlamydial. Fungal (Coccidioides immitis)
Parasitic (Trichomonas species, Toxoplasma gondii), 
Viral (especially Herpes simplex)
Drug reactions, most commonly to: antibiotics (including, sulphonamides, penicillin), anticonvulsants (phenytoin, barbiturates), aspirin, modafinil, antituberculoids, and allopurinol and many others. Physical factors: radiotherapy, cold, sunlight
Others: collagen diseases, vasculitides, non-Hodgkin lymphoma, leukaemia, multiple myeloma, myeloid metaplasia, polycythemiaEM minor is regarded as being triggered by HSV in almost all cases. A herpetic etiology also accounts for 55% of cases of EM major. Among the other infections, Mycoplasma infection appears to be a common cause. Herpes simplex virus suppression and even prophylaxis (with acyclovir) has been shown to prevent recurrent erythema multiforme eruption. Treatment
Erythema multiforme is frequently self-limiting and requires no treatment. The appropriateness of glucocorticoid therapy can be uncertain, because it is difficult to determine if the course will be a resolving one. See also
Erythema multiforme major
Erythema multiforme minor
Toxic epidermal necrolysis
Stevens–Johnson syndrome

References


== External links ==
Starting in the 1950s, ethinylestradiol became widely used in birth control pills. Estradiol-containing birth control pills were initially studied in the 1970s, with the first report published in 1977. Development of birth control pills containing estradiol was motivated by the thrombotic risks of ethinylestradiol that were uncovered in the 1960s and 1970s. More than 15 attempts were made at development of an estradiol-containing birth control pill starting in the 1970s, but were unsuccessful due to unacceptable menstrual bleeding patterns. Estradiol valerate/cyproterone acetate (Femilar) was introduced for use as a birth control pill in Finland in 1993, but was never marketed elsewhere. Subsequently, estradiol valerate/dienogest (Natazia, Qlaira) was marketed as a birth control pill in 2008 and estradiol/nomegestrol acetate (Naemis, Zoely) was introduced in 2012. Society and culture
Generic names
Estradiol is the generic name of estradiol in American English and its INN, USAN, USP, BAN, DCF, and JAN. Estradiolo is the name of estradiol in Italian and the DCIT and estradiolum is its name in Latin, whereas its name remains unchanged as estradiol in Spanish, Portuguese, French, and German. Oestradiol was the former BAN of estradiol and its name in British English, but the spelling was eventually changed to estradiol. When estradiol is provided in its hemihydrate form, its INN is estradiol hemihydrate. Brand names
Estradiol is marketed under a large number of brand names throughout the world.