It is an open study, explorative, proof of concept study concerning mycobiota dysbiosis implication in AD patients with head and neck involvement.

The aim of this study is to carry out an analysis of the mycobiome in the head and neck regions of 30 adults with Atopic dermatitis compared with 15 healthy controls.

patients and participants will be recruited from 2 centers Hôpital Tenon AP-HP (Pr A Soria) and CHU Lille (Pr D Staumont-Sallé) over a 12-month period.

Patient will be classified in 2 subgroups according to topography and body surface area involved by AD;

• Group 1: Generalized AD defined by AD skin lesion involved more or equal 50% of total body surface area with head and neck involvement. (15 patients)
• Group 2: Head and neck AD (HNAD) defined by AD involving at least 80% of the head and neck area with or without AD involvement outside the head and neck area but <20% of total body surface area. (15 patients) Group 3: Healthy control without chronic skin disease. Healthy control will be recruited from non-atopic patients explored in ours departments for drug allergy after resolution of acute events. (15 healthy controls) In the framework of consultation, medical examination with clinical assessment, non-invasive skin microbiota samples (3x2 skin ESwab) will be performed and a supplemental blood sample was collected (35 mL) for study of innate and adaptive immune response (see Diagram of the study summarising the chronology of the study). For each patient the end of participation in the study is achieved after the completion of swab and blood samples. No follow up is planned. Patients' participation is 1 day at maximum.

Skin samples will be used for study of Mycobiome by culture and MALDI-TOF and NGS analysis and Blood sample will be used for study of the immune innate and adaptative response.

Inclusion Criteria:

• Age between 18 and 65 years;
• Male or female;
• The diagnosis of atopic dermatitis (AD) is defined according to the criteria of UK Working Party with at least 3 of the following 5 criteria are present; history of flexural involvement, history of a dry skin, onset under the age of 2, personal history of asthma or allergic rhinitis, history of a pruritic skin condition, and visible flexural dermatitis.
• Generalized AD defined by AD involved ≥50% of total body surface area with head and neck involvement. Or HNAD defined by AD involving at least 80% of the head and neck area with or without AD involvement outside the head and neck area but <20% of total body surface area.
• With or without topical anti-inflammatory treatments for AD (including; topical steroids and/or topical tacrolimus)
• Free, informed and written consent, signed by the patient and the investigator before any examination required by the trial;
• Affiliation to social security scheme (beneficiary or assignee)
• Healthy control are the same age and sex.

Exclusion Criteria:

• Systemic or local antifungal therapy within 2 months before entry and during the study
• Systemic treatments for AD; including: ciclosporine, dupilumab and others AD biologics, methotrexate, JAK-inhibitors
• Current participation in another interventional research
• Patient with a measure of legal protection
• Psychiatric illness or any other concomitant chronic illness or addiction that could be interfere with the ability to meet the requirements of the protocol or provide informed consent

Adult, age between 18 and 65 years with generalized and head and neck AD treated with topical steroids and/or topical tacrolimus for AD.