The physiological states of the skin are characterized by a certain homeostasis linked to the balance of the metabolic pathways. When these pathways are deregulated, the proteic, lipidic and metabolic is affected. It is thus possible to follow a change in the state of the skin by looking at change in the associated molecular profile.

The PRISM laboratory (INSERM U1192) in Lille has developed an innovative system laser called SpiderMass composed of 4 parts:

1. A laser used for the micro-sampling of material in vivo,
2. A transport transfer line of the ablated particles,
3. A mass spectrometer that analyzes them in real time and generates the molecular profiles of the epidermis,
4. A data analysis procedure.

The SpiderMass(TM) is of great interest for the study of the skin because it allows non-invasive vivo characterization, and therefore without biopsy or sample preparation. In addition, it will complement techniques already used in the research center such as FTIR spectroscopy. Indeed, in acne studies the FTIR allows to obtain only the Fatty Acid Triglycerid ratio while the SpiderMass permits to detail these lipid classes by each observed molecule on the surface of the skin and follow their evolution.

--> INCLUSION CRITERIA

CRITERIA RELATED TO THE POPULATION:

• Male or female subject having signed a written informed consent for his/her participation to the study
• Subject with a phototype II to IV according to the Fitzpatrick scale
• Subject affiliated to a social security system or health insurance, or is a beneficiary
• For woman of childbearing potential use of an effective method of contraception, as assessed by the investigator for at least 4 weeks before inclusion in the study

For acne of the face subgroup and its associated control: Male or female, 18 to 30 years old included

For atopic dermatitis of the upper limb subgroup and its associated control: Male or female, 20 to 50 years old included

For vulgar plaque psoriasis subgroup and its associated control: Male or female, 20 to 55 years old included

For telangiectasic erythrocouperosis papule of the face (rosacea) subgroup and its associated control: Male or female, 30 to 55 years old included

For seborrheic dermatitis of scalp subgroup and its associated control: Male or female, 20 to 45 years old included

CRITERIA RELATED TO DERMATOSIS:

For subjects of the acne of the face subgroup :

-Subjects with mild to severe acne on the face with a GEA (Global Acne Evaluation) score of 2 to 4 on a rating scale ranging from 0 (no injury) to 5 (very severe)

• Subject presenting on the face, at least one zone:

  • Lesional in immediate border of a papule
  • Peri-lesional near inflammatory lesions (papule, about 1 cm)

• Subject presenting on the inner side of the forearm a reference zone without lesion

For subjects in the atopic dermatitis subgroup of upper limbs:

• Subject with atopic dermatitis on the upper limbs, mild to moderate with SCORAD (SCORing Atopic Dermatitis) between 15 and 40 included with:

  •A dryness score ≥ 2 on a scale ranging from 0 (absent) to 3 (severe)

• Subject having at least one inflammatory flare of atopic dermatitis on the upper limbs in the 2 years before the day of inclusion

• Subject presenting on the upper limb (hand excluded) at least one zone:

  •Lesional defined by the signs of target SCORAD between 3 and 12:

  • Erythema from 1 to 3

  • Dryness ≥2

  • Oedema / papule from 0 to 3

  • Lesions oozing or crusting 0
  • Excoriation of 0
  • Lichenification from 0 to 3 On a scale ranging from 0 (absent) to 3 (severe)
  • Peri-lesional near the lesion zone (about 1cm)

• Subject presenting on the inner side of the forearm a reference zone without lesion

For vulgar plaque psoriasis subgroup

• Subject with mild to moderate erythematous-squamous plaque psoriasis whose IGA (Investigator Global Assessment) score is between 2 and 3, on a rating scale ranging from 0 (clear) to 5 (very severe)

• Subject with on the upper limb (hand excluded) or lower limb at least one zone:

  • Lesional:
  • Without fissure and without crust
  • With erythema score ≥ 1 on a scale ranging from 0 (absent) to 3 (severe)
  • With desquamation score between 1 (mild) and 2 (moderate) on a scale ranging from 0 (absent) to 3 (severe)
  • With an oedema score of 0 (absent) on a scale ranging from 0 (absent) to 3 (severe)
  • Peri-lesional:
  • Without fissure and without crust
  • Near the lesion zone (about 1 cm)
  • Subject presenting on the inner side of the forearm a reference zone without lesion

For telangiectasic erythrocouperosis papule of the face (rosacea) subgroup

- Subject with telangiectasic erythrocouperosis and papule of the face mild to moderate with an IGA score between 2 and 3 on a rating scale ranging from 0 (absent) to 4 (severe)

• Subject presenting on the face at least one zone:

  • Lesional: immediate border of the papule with a persistent erythema score ≥ 1 on a rating scale ranging from 0 (absent) to 3 (severe)

  • Peri-lesional:

  • Near inflammatory lesions (papule, about 1 cm)

  • Ranging of at least 1 point less in the erythema score compared to the lesion zone

• Subject presenting on the inner side of the forearm a reference zone without lesion

For seborrheic dermatitis of scalp subgroup :

• Subject with mild to moderate seborrheic dermatitis with an IGA score between 2 and 3 on a rating scale ranging from 0 (absent) to 4 (severe)

• Subject presenting on the scalp at least one zone:

  • Lesional:
  • with erythema score ≥ 1 on a scale of 0 (absent) to 3 (severe)
  • with clinically visible scales
  • Peri-lesional:Near the lesion zone (about 1 cm)

• Subject presenting on the inner side of the forearm a reference zone without lesion

  • NON INCLUSION CRITERIA

CRITERIA RELATED TO THE POPULATION:

• For woman of childbearing potential: pregnant or breastfeeding
• Subject unable to understand the information given including study procedures (for linguistic or psychiatric reasons) and to give his/her consent in writing
• Subject who, in the judgement of the investigator, is not likely to be compliant with study-related constraints and requirements
• Subject who has forfeited his/her freedom by administrative or legal award or is under guardianship
• Subject who is in a position likely to represent a conflict of interest and/or is a family member of any people involved in the conduct of the study (secretary, nurse, technician…) of the investigational site
• Subject who is currently participating, who plans to participate or who has participated in another clinical study liable to interfere with the study assessments according to the investigator's assessment

CRITERIA RELATED TO DERMATOSIS AND CUTANEOUS CONDITION:

• Subject with premature cutaneous aging linked to a genetic disease
• Subject with solar erythema in at least one zone under study
• Subject with a tattoo, scar or other dermatological sign on at least one study zone that may interfere with the study according to the investigator's assessment
• Subject with autoimmune disease
• Subject with any type of complication on at least one study area (excoriation type, primary, viral, fungal or parasitic bacterial infection, etc.) according to the investigator's assessment

Criteria for control subgroups:

- Subject with a dermatosis or any type of lesion on the zone corresponding to the lesional, peri-lesional zone or reference zone of the associated subgroup dermatosis likely to interfere with the study according to the investigator's assessment

Criteria for chronic inflammatory dermatitis:

For subjects of the acne of the face subgroup:

- Subject with another dermatosis (chronic / acute, inflammatory, infectious, immune) on the face that could interfere with the study according to the investigator's assessment

For subjects in the atopic dermatitis subgroup of upper limbs:

- Subject with another dermatosis (chronic / acute, inflammatory, infectious, immune) on the upper limb (s) to the study likely to interfere with the study according to the investigator's assessment

For vulgar plaque psoriasis subgroup

• Subject with an isolated palmo-plantar form of psoriasis
• Subject with an isolated form of cutaneous psoriasis other than in plaque (in gout, pustular, erythrodermic or inverted elbow creases (psoriasis of the mucous membranes))
• Subject with another dermatosis (chronic / acute, inflammatory, infectious, immune) on the upper limb (s) and/or lower limb(s) to the study likely to interfere with the study according to the investigator's assessment

For telangiectasic erythrocouperosis papule of the face (rosacea) subgroup

- Subject with another dermatosis (chronic / acute, inflammatory, infectious, immune) on the face that could interfere with the study according to the investigator's assessment

For seborrheic dermatitis of scalp subgroup :

• Seborrheic dermatitis under medical treatment
• Subject with another dermatosis (chronic / acute, inflammatory, infectious, immune) on the scalp likely to interfere with the study according to the investigator's assessment (in particular contact eczema or alopecia)

CRITERIA RELATED TO TREATMENTS AND PRODUCTS

For all subjects :

• Oral intake of isotretinoin or acitretin (oral vit-A and derivatives) within the 6 months prior to the inclusion visit or the day of the visit
• Local retinoid treatment on at least one study zone, which may interfere with the results of the study according to the investigator's assessment within the month preceding the inclusion visit or the day of the visit
• Phototherapy treatment in at least one study zone within 4 weeks prior to the inclusion visit or the day of the visit
• Topical or oral treatment established or modified during the previous weeks or to be established or modified during the study, which may interfere with the results of the study according to the investigator's assessment ( for example modifying the cutaneous characteristics: treatment inducing pigmentation), keratolysis, ...)
• Anti-inflammatory treatment (steroidal or nonsteroidal) taken daily and repeatedly for more than 5 consecutive days during the week preceding the inclusion visit
• Application of any topical vitamin D-derived treatment on at least one study zone within 3 weeks prior to the inclusion visit or the day of the visit
• Application of dermocorticoid topical or immunomodulatory topical treatments (tacrolimus), antifungals, local antibiotics on at least one study zone in the 3 weeks prior to the inclusion visit or the day of the visit
• Application of water, product or topical treatment on at least one zone under study after the last wash the day before the visit
• Application of water, topical product or make-up on at least one zone the day of the inclusion visit

For seborrheic dermatitis of scalp subgroup and its associated control :

• Use on the scalp of any product that can be active on squamous conditions, rinsed or posed (anti-dandruff, anti-fungal shampoo, vinegar rinse, essential oils ...) within 2 weeks prior to the inclusion visit or the day of the visit
• Any technique to change the color or condition of the hair (coloring, discoloration, permanent, smoothing / straightening, ..) performed within 2 weeks prior to the inclusion visit or the day of the visit
• Washing of the scalp done within 2 days before the inclusion visit or the day of the visit