Can scalp chemistry explain stubborn itching without dandruff?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Female volunteer from 18 to 50 years old, in good general health (physical, mental, and social well-being) according to volunteer self-declaration and investigator's opinion. 2. Female of childbearing potential who is not sexually active, or who is using an effective contraceptive method for at least one month before the beginning of the study and throughout the study. 3. Female of childbearing potential willing to undergo urine pregnancy test. 4. Volunteer has the life habit of washing hair twice to 7 times every week. 5. Volunteer has scalp conditions based on group: a. Group 1 i. Self-declared normal scalp without pruritus, score=0 on pruritus Visual Analog Scale (VAS). ii. Adherent dandruff score ≤0.5 based on Dandruff Photographic Scales (DFS) assessed by dermatologist. b. Group 2 i. Scalp pruritus score ≥4 and ≤8 on pruritus VAS. ii. Adherent dandruff score ≥2 and ≤4 based on DFS assessed by dermatologist. c. Group 3 i. Scalp pruritus score ≥4 and ≤8 on pruritus VAS. ii. Adherent dandruff score ≤0.5 based on DFS assessed by dermatologist. 6. Volunteer with Asian scalp. 7. Volunteer living in Shanghai for at least one year. 8. Volunteer willing and able to fulfil the study requirements and schedule. 9. Volunteer informed about the study objectives and procedures, and able to understand them. 10. Volunteer who has given written informed consent. Exclusion Criteria: 1. Volunteer who is pregnant or lactating or who is planning to become pregnant during the study. 2. Menopausal female (with absence of menstruations for less than one year) or post-menopausal female (with absence of menstruations for more than one year). 3. Volunteer who has hair treatments including hair coloration, bleaching or perm within 3 months before inclusion. 4. Volunteer who has skin cancer, severe autoimmune skin diseases or other moderate or severe skin diseases. 5. Volunteer who has Seborrheic dermatitis, psoriasis, scalp pityriasis, tinea capitis, atopic dermatitis, folliculitis, alopecia or other skin disorders might interfere the assessment on scalp or calves determined by the dermatologist. 6. Volunteer who has diagnosed endocrine disorders (e.g. hypopituitarism, diabetes mellitus, polycystic ovary syndrome), auto-immune medical conditions (e.g. systemic lupus erythematosus (SLE) and Rheumatoid arthritis (RA)), hyper- or hypothyroidism, hypertension or mental illness (e.g. diagnosed depression, schizophrenia, trichotillomania). 7. Volunteer who has active gastrointestinal (GI) bleeding or history of heart or vascular disease. 8. Volunteer who has systemic medication (e.g. steroidal and non-steroidal anti-inflammatory drugs, corticoids, insulin, antihistamines, hormones, antihypertensive, antibiotics such as quinolone, tetracycline, thiazides, fluoroquinolones) within one month before inclusion. 9. Volunteer who has topical treatments of prescription, over-the-counter remedies (e.g. minoxidil, ketoconazole, selenium sulfide lotion) on scalp within 2 months before inclusion. 10. Volunteer who changed her routine shampoo within 2 weeks before inclusion. 11. Volunteer who has conditions considered by the Investigator as sound reasons for disqualification from enrolment into the study, because it might put the individual at significant risk, confound study results or interfere with the individual's participation. 12. Volunteer who declares to be deprived of freedom by administrative or legal decision. 13. Volunteer who cannot be contacted by phone in case of emergency. 14. Volunteer having participated within 30 days before inclusion or currently participating in another clinical study.