Severe Bullous Drug Eruption and Filgrastim

• Filgrastim (Drug), also known as ZARZIO: Injection of ZARZIO 30 MU/0,5mL and/or ZARZIO 48 MU/0,5mL, over a period of 5 consecutive days (1 injection per day during 30 minutes - - day 1 : set up standard treatment). The filgrastim solution will be diluted in 20 mL of 5% Glucose. The dose of ZARZIO administrated depends of the patient's weight : * 20 to < 30kg = 0,3 mL of ZARZIO 48 MU/0,5mL (subcutaneous route) * 30 to < 60kg = 0,5 mL of ZARZIO 30 MU/0,5mL (by IV) * 60 to < 90kg = 0,5 mL of ZARZIO 48 MU/0,5mL (by IV) * 90 to < 120kg = 2x0,5 mL of ZARZIO 30 MU/0,5mL (by IV) * 120 to 150kg = 0,5 mL of ZARZIO 30 MU/0,5mL + 0,5 mL of ZARZIO 48 MU/0,5mL (by IV) * > 150kg = 2x0,5 mL of ZARZIO 48 MU/0,5mL (by IV)
• Placebo (Drug), also known as GLUCOSE 5%: Injection of 20 mL of Glucose 5% solution over a period of 5 consecutive days (1 injection per day during 30 minutes - day 1 : set up standard treatment). The dose given is equivalent to that used for filgrastim : * 20 to < 30kg = placebo not available because the injection must be done subcutaneously so the blind cannot be respected. * 30 to < 60kg = 20mL of Glucose 5% solution (by IV) * 60 to < 90kg = 20mL of Glucose 5% solution (by IV) * 90 to < 120kg = 20mL of Glucose 5% solution (by IV) * 120 to 150kg = 20mL of Glucose 5% solution (by IV) * > 150kg = 20mL of Glucose 5% solution (by IV)

Primary outcomes

• Arrest of the SJS/NET progression at day 5 [On day 5 (after 5 injections of ZARZIO or PLACEBO - D0: initiation of treatment)]: Comparison between the 2 arms of the proportion of patients with arrest of progression of skin detachment defined by a peeled surface and/or bullous and/or associated at a NIKOLSKY sign determined according to the stable burn table - Evaluation done by the Outcomes Assessor and the adjudication committee.

Secondary outcomes

• Arrest of the SJS/NET progression [At day 3, day 7 and day 15]: Comparison between the 2 arms of the time until the arrest of the SJS/NET progression defined by a peeled surface and/or bullous and/or associated at a NIKOLSKY sign determined according to the stable burn table - Evaluation done by the Outcomes Assessor and the adjudication committee.
• Complete re-epidermization [At day 3, day 5, day 7, day 15 and day 45]: Comparison between the 2 arms of the time until the complete re-epidermization defined by the disappearance of skin rashes and return to normal skin. Evaluation done by the Outcomes Assessor and the adjudication committee.
• Overall survival [Until 30 days]: Comparison between the 2 arms of the overall survival
• Overall survival [Until 1 year]: Comparison between the 2 arms of the overall survival
• Duration of hospitalization [15 days (maximal of SJS/NET episode's hospitalization)]: Comparison between the 2 arms of the number days of hospitalization corresponding to the duration of SJS/NET episode's hospitalization.
• Premature discontinuation of experimental treatment [Between day 0 and day 5]: Number of clinical and biological adverse event leading to stop the filgrastim treatment (per patient, nature and grade of the AE (adverse event ) - repository CTCAE version 5.0)
• Adverse events [Until 1 year]: Comparison between the 2 arms of the number of clinical and biological adverse event (by organ systems - repository CTCAE version 5.0)..
• Use of systemic corticosteroid therapy [Between day 0 and day 15]: Study of the nature, cumulative doses and indications objectifying a corticosteroid prescription. A comparison between the 2 arms will be done.
• Evaluation of sequels [At day 45, day 60, day 90, day 180 and 1 year]: Determination of the proportion of patients with at least one sequel among the following specialty : ophthalmology, stomatology/ORL(otorhinolaryngology), gastroenterology, gynecology, urology and psychiatry, researched during specialized consultations during the remote monitoring phase. A comparison between the 2 arms will be done.
• Quality of life evolution [At day 60, day 180 and 1 year]: Quality of life evolution assessed with Dermatology Life Quality Index (DLQI) or Children's Dermatology Life Quality Index (CDLQI). DLQI is calculated by adding the score of each question, resulting in a maximum of 30 and a minimum of 0. The higher the score, the more quality of life is impaired. CDLQI is used in the same way. It is documented in 5 minutes. Each question is illustrated by a cartoon based on the theme of the question, making it more fun for younger children. The scoring for each question is "Very much"\[Score = 3\], "Quite a lot"\[2\], "Only a little"\[1\], "Not at all"\[0\], "Blank"\[0\], and Q7 - "prevented school"\[3\]. The 10 individual question scores are summed to provide a total CDLQI score. The maximum possible score is 30, indicating maximum impact on QoL. A comparison between the 2 arms will be done.
• Risk of developing Post Traumatic Stress Disorder (PTSD) [At day 0, day 7 and day 15]: Determination of the proportion of patients with high risk of developing PTSD measured with Impact of Event Scale Revised (IES-R) or Children's Revised Impact of Event Scale (CRIES). IES-R is a 22-item self-administered questionnaire that measures symptoms of intrusion, avoidance and over-arousal experienced during the past 7 days. Patients rate each item on a 0-5 point Likert scale. The total score, between 0 and 88, is obtained by adding all the ratings for each item: low risk (score less than 12), moderate (score between 12 and 34 inclusive) or at high risk (score strictly greater than 34) of developing PTSD. CRIES-13 is a revised scale to measure the impact of events on children from 8 years old. Items are rated on a 4-point scale, with scores of 0, 1, 3 and 5 points. The maximum score is 65. The score is obtained by adding the responses to each item. A score of 30 or more would be effective in screening for PTSD. A comparison between the 2 arms will be done.

Sex: All, ages: 6 Years to any

Inclusion Criteria:

* Patient aged of 6 years old or more, presenting SJS/TEN, drug or infectious origin proofed and very strongly suspected (indirect certainty argument), confirmed by evaluator.
* SJS or TEN evolving since less than 7 days with a progression of the detachment or the eruption observed dating less than 48 hours.
* Patient and/or have right able to understand the objectives of the trial and having given their written consent to participate (parents for minors, have right for patients in immediate life-saving emergency).
* Patient registered with a social security scheme or benefiting from a similar scheme.
* Pregnancy test beta HCG negative for women of childbearing age

Exclusion Criteria:

* Patient weighing less than 20kg
* Chronic myeloid pathology such as myeloid leukemia or AML (acute myeloid leukemia)
* Thrombophilia or thrombotic pathology in progress
* PNN (polymorphonuclear neutrophils) > 50.000/mm3 on the CBC (Complete Blood Count) during the inclusion visit
* Administration of G-CSF or GM-CSF within 5 days of inclusion
* Patient who received cyclosporine, anti-TNFalpha or intravenous immunoglobulins or lithium in the month prior the inclusion
* Pregnant or breastfeeding woman
* Patient under protective measure (safeguard measure, curatorship, guardianship) or deprived of liberty
* Patient in exclusion period after participation at other interventional clinical trial
* Known hypersensitivity to the active substance (FILGRASTIM) or to the one of the excipients (glutamine acid, sorbitol E420, Polysorbate 80)
* Patient presenting a known glucose intolerance or hereditary fructose intolerance
* Patient with a traumatic brain injury less than 24 hours
* Patient admitted with septic shock