This is a randomized, double-blind, placebo-controlled parallel group study on the efficacy and safety of intramuscular injections of autologous immunoglobulin in patients with moderate-to-severe atopic dermatitis.

Children and adult patients with moderate-to-severe atopic dermatitis (age ≥ 13 years) whose clinical conditions have not been effectively controlled by current standard medical therapies (topical moisturizers, topical corticosteroids, topical calcineurin inhibitors, and oral antihistamines) for more than 2 months will be include.

This is a randomized, double-blind, placebo-controlled parallel group study on the efficacy and safety of intramuscular injections of autologous immunoglobulin in patients with moderate-to-severe atopic dermatitis. After providing informed consent, patients will be assessed for study eligibility at the baseline visit. Patients will undergo screening within 28 days prior to randomization as "wash out period", and during the screening period, treatment with medications (including systemic corticosteroids and systemic immunomodulating agents) for atopic dermatitis will be wash-out for at least 28 days prior to baseline (exclude moisturizers).

At screening, plasma will be separated from patients' venous blood (400ml) aseptically and autologous immunoglobulin (total IgG) will be purified from the plasma by chromatography using Protein A during the screening period. Patients will be randomized in a 1:1 ratio to receive weekly treatment with autologous immunoglobulin or placebo (normal saline) will be administrated by intramuscular injection, once a week for 7 weeks (total 8 injections).

The investigators will evaluate the clinical efficacy and safety of intramuscular injections of autologous immunoglobulin in those patients with moderate-to-severe atopic dermatitis by measuring changes in the standardized clinical severity scoring system for atopic dermatitis (SCORAD) values, Eczema Area and Severity index (EASI) and quality of life together with laboratory parameters in blood samples before and after treatment. Systemic corticosteroids as a rescue treatment will be prescribed to control unacceptable symptoms of atopic dermatitis at the investigator's discretion.

Inclusion Criteria:

1. Suitability of autologous blood donation criteria
2. Current standard medical therapies more than 2 months and moderate-to-severe atopic dermatitis
3. ≥10% lesion body surface area (BSA) of atopic dermatitis involvement in area

Exclusion Criteria:

1. Patients under the age of 13 year.
2. Patients who are unable to agree on their own (emergency patients, patients with mental disability, patients with limited capacity to consent due to stroke or delirium caused by diabetes).
3. Patients with severe disease whose expected survival duration is less than 3 months.
4. Pregnancy or planned pregnancy within 1 year
5. Skin condition not appropriate for blood sampling and transfusion
6. The standardized clinical severity scoring system for atopic dermatitis (SCORAD) values <25 (Mild atopic dermatitis)