Chronic Plaque-type PsoriasisNCT07844772
Serum Substance P, Neuropathic Pain, and Central Sensitization Across Treatment Groups in Chronic Plaque Psoriasis
An observational study of Chronic Plaque-type Psoriasis, run by Istanbul Training and Research Hospital at 1 site in Turkey (Türkiye).
Trial summary
The goal of this observational study is to better understand whether blood levels of Substance P are related to pain, itching, altered pain sensations, central sensitization, psoriasis severity, and quality of life in adults with chronic plaque psoriasis. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Chronic Plaque-type Psoriasis
- What is being tested?
- IL-17 Inhibitor Therapy and Conventional Systemic Therapy
- How many people
- 100 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 11 Jun 2026to Jan 2027
- Phase
- Observational
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Adults with chronic plaque psoriasis who are followed at the Dermatology Department of Istanbul Training and Research Hospital and meet the study eligibility criteria will be included. Participants will be classified into three predefined groups according to their current psoriasis treatment: IL-17 inhibitor therapy, conventional systemic therapy with methotrexate or acitretin, and topical therapy only or treatment-naive. Participants will undergo clinical, patient-reported, laboratory, and neurological assessments during a single cross-sectional study period.
Who may be able to join
- Age ≥18 years
- Diagnosis of chronic plaque psoriasis
- Ability and willingness to provide written informed consent
- For the IL-17 inhibitor group: current treatment with an IL-17 inhibitor for at least 8 weeks
- For the conventional systemic therapy group: current treatment with methotrexate or acitretin for at least 6 weeks
- For the topical therapy/treatment-naive group: topical therapy only or no previous treatment, with no systemic therapy, biologic therapy, or phototherapy within the previous 6 months
Who cannot join
- Known diabetes mellitus, HbA1c ≥6.5%, or fasting plasma glucose ≥126 mg/dL
- Vitamin B12 level <200 pg/mL
- Known peripheral neuropathy or peripheral neuropathy detected during neurological evaluation and/or electromyography
- Neuropathy related to uremia or thyroid disease
- Chronic renal failure or chronic liver failure
- Active infection
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- Active malignancy
- Active inflammatory arthritis in patients with psoriatic arthritis
- Pregnancy or breastfeeding
- Chronic heavy alcohol use
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)1 site, 1 recruiting
- Recruiting
Istanbul Training and Research Hospital
Istanbul, Istanbul, 34098
Yasemin Dündar Şahin, +905394254565, yasemindundar97@gmail.com
About this study
Official title: Evaluation of the Association of Serum Substance P Levels With Neuropathic Pain, Central Sensitization, Disease Severity, and Quality of Life Across Different Treatment Groups in Patients With Chronic Plaque Psoriasis
The goal of this observational study is to better understand whether blood levels of Substance P are related to pain, itching, altered pain sensations, central sensitization, psoriasis severity, and quality of life in adults with chronic plaque psoriasis.
The main questions this study aims to answer are:
Read more
Are serum Substance P levels associated with neuropathic pain features, central sensitization, psoriasis severity, pain, itching, and quality of life? Do serum Substance P levels and these clinical features differ among patients receiving different psoriasis treatments?
Researchers will compare three groups of patients: those receiving IL-17 inhibitor treatment, those receiving conventional systemic treatment with methotrexate or acitretin, and those receiving topical treatment only or no current treatment.
Participants will:
Have their psoriasis severity assessed and complete questionnaires about pain, itching, central sensitization, and quality of life.
Undergo a neurological examination. Participants who report pain will also be evaluated for neuropathic pain features using the DN4 questionnaire.
Provide a blood sample for measurement of serum Substance P and routine laboratory tests.
Undergo electromyography and nerve conduction studies if peripheral neuropathy is suspected during the neurological evaluation.
No treatment will be assigned or changed as part of this study.
Read the detailed description
Psoriasis is a chronic, immune-mediated inflammatory skin disease characterized by complex interactions between immune pathways, cutaneous inflammation, and the nervous system. In addition to visible skin lesions, patients may experience pruritus, pain, burning, tingling, and other sensory complaints that can substantially impair quality of life. Increasing evidence suggests that neuroimmune mechanisms may contribute to these symptoms. Substance P, a neuropeptide involved in neurogenic inflammation, nociception, and pruritus, may represent one of the mediators linking cutaneous inflammation with sensory symptoms in psoriasis. The IL-17 pathway may also interact with neuroimmune mechanisms involved in pain and pruritus.
This single-center, cross-sectional, observational study aims to investigate the relationship between serum Substance P levels and clinical features including neuropathic pain characteristics, central sensitization, psoriasis severity, pain intensity, pruritus intensity, and dermatology-related quality of life in adults with chronic plaque psoriasis. The study will also explore whether serum Substance P levels and clinical characteristics differ according to the patients current treatment approach.
Approximately 100 patients with chronic plaque psoriasis will be enrolled and evaluated in three treatment groups: patients receiving IL-17 inhibitor therapy, patients receiving conventional systemic therapy such as methotrexate or acitretin, and patients receiving topical therapy only or no current treatment. Treatment history and duration of current therapy will also be recorded.
Psoriasis severity will be assessed using the Psoriasis Area and Severity Index (PASI), and quality of life will be evaluated using the Dermatology Life Quality Index (DLQI). Pain and pruritus intensity will be recorded using Numeric Rating Scales (NRS), and central sensitization symptoms will be evaluated using the Central Sensitization Inventory (CSI).
The presence and localization of pain will be recorded, including whether the pain is associated with psoriatic plaques. In participants reporting pain, neuropathic pain characteristics will be assessed using the Douleur Neuropathique 4 Questions (DN4). DN4 scores will be recorded both as total scores and according to the validated cutoff, with scores of 4 or higher considered positive for neuropathic pain features. Participants without pain will not undergo DN4 assessment.
All participants will undergo a standardized neurological evaluation in collaboration with the Neurology Department. Neurological examination will include assessment for findings suggestive of peripheral neuropathy. Electromyography and nerve conduction studies will be performed when peripheral neuropathy is clinically suspected, and participants with confirmed peripheral neuropathy will be excluded from the relevant study analyses according to the study protocol.
Venous blood samples will be obtained for measurement of serum Substance P concentrations using an enzyme-linked immunosorbent assay (ELISA). Laboratory assessments will also include parameters used to identify potential causes of peripheral neuropathy or relevant systemic confounders, including glycated hemoglobin (HbA1c), fasting glucose, vitamin B12, renal and liver function tests, thyroid function tests, complete blood count, erythrocyte sedimentation rate, and C-reactive protein, as clinically appropriate.
The primary analyses will examine the associations between serum Substance P concentrations and clinical measures of neuropathic pain features, central sensitization, psoriasis severity, pain, pruritus, and quality of life. Comparisons across the three treatment groups will also be performed to explore whether neuroimmune and clinical profiles differ according to treatment exposure.
- Conditions
- Chronic Plaque-type Psoriasis
- Being tested
- IL-17 Inhibitor Therapy, Conventional Systemic Therapy
- Keywords
- Central Sensitization, Interleukin-17 Inhibitors, Substance P, Neuropathic Pain, Pain, Pruritus, Quality of Life
- Medical subject headings
- Neuralgia, Pain, Pruritus
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
IL-17 Inhibitor TherapyBiological
Exposure to IL-17 inhibitor therapy prescribed as part of routine clinical care for chronic plaque psoriasis. Treatment is not assigned, initiated, or modified by the study. Participants are classified according to their current treatment at the time of study assessment.
Conventional Systemic TherapyDrug
Exposure to conventional systemic therapy with methotrexate or acitretin prescribed as part of routine clinical care for chronic plaque psoriasis. Treatment is not assigned, initiated, or modified by the study.
| Study group | Role | What they receive |
|---|---|---|
| IL-17 Inhibitor Group | Patients with chronic plaque psoriasis receiving an IL-17 inhibitor as part of routine clinical care. Participants are included according to their existing treatment, and no treatment is assigned or modified by the study. Receives: Biological: IL-17 Inhibitor Therapy | |
| Conventional Systemic Therapy Group | Patients with chronic plaque psoriasis receiving conventional systemic treatment with methotrexate or acitretin as part of routine clinical care. No treatment is assigned or modified by the study. Receives: Drug: Conventional Systemic Therapy | |
| Topical Therapy or Treatment-Naive Group | Patients with chronic plaque psoriasis receiving topical therapy only or who have not yet received any treatment for psoriasis. Participants in this group have not received systemic therapy, biologic therapy, or phototherapy within the previous 6 months. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Association Between Serum Substance P Levels and DN4 Score
The association between serum Substance P concentration measured by ELISA and the total Douleur Neuropathique 4 Questions (DN4) score will be evaluated among participants who report pain and undergo DN4 assessment. DN4 scores range from 0 to 10, with scores ≥4 considered positive for neuropathic pain features.
Measured: Baseline (Day 1)
Association Between Serum Substance P Levels and Central Sensitization Inventory Score
The association between serum Substance P concentration and the Central Sensitization Inventory (CSI) Part A total score will be evaluated. Part A consists of 25 items, with total scores ranging from 0 to 100. Higher scores indicate a greater burden of symptoms associated with central sensitization.
Measured: Baseline (Day 1)
Association Between Serum Substance P Levels and Psoriasis Severity
The association between serum Substance P concentration and psoriasis severity measured by the Psoriasis Area and Severity Index (PASI) will be evaluated. PASI ranges from 0 to 72, with higher scores indicating greater disease severity.
Measured: Baseline (Day 1)
Association Between Serum Substance P Levels and Pain Intensity
The association between serum Substance P concentration and pain intensity measured using a 0-10 Numeric Rating Scale (NRS) will be evaluated, with higher scores indicating greater pain intensity.
Measured: Baseline (Day 1)
Association Between Serum Substance P Levels and Pruritus Intensity
The association between serum Substance P concentration and pruritus intensity measured using a 0-10 Numeric Rating Scale (NRS) will be evaluated, with higher scores indicating greater pruritus intensity.
Measured: Baseline (Day 1)
Association Between Serum Substance P Levels and Dermatology-Related Quality of Life
The association between serum Substance P concentration and the Dermatology Life Quality Index (DLQI) score will be evaluated. DLQI ranges from 0 to 30, with higher scores indicating greater impairment in quality of life.
Measured: Baseline (Day 1)
Secondary outcomes (7)
Differences in Serum Substance P Levels Across Treatment Groups
Serum Substance P concentrations will be compared among participants receiving IL-17 inhibitor therapy, conventional systemic therapy with methotrexate or acitretin, and topical therapy only or no previous/current systemic treatment according to the study group definitions.
Measured: Baseline (Day 1)
Psoriasis Area and Severity Index (PASI) Score Across Treatment Groups
The Psoriasis Area and Severity Index (PASI) total score will be compared across the three predefined treatment groups. Scores range from 0 to 72, with higher scores indicating greater psoriasis severity.
Measured: Baseline (Day 1)
Central Sensitization Inventory (CSI) Score Across Treatment Groups
The Central Sensitization Inventory (CSI) Part A total score will be compared across the three predefined treatment groups. Part A consists of 25 items, with total scores ranging from 0 to 100. Higher scores indicate a greater burden of symptoms associated with central sensitization.
Measured: Baseline (Day 1)
Dermatology Life Quality Index (DLQI) Score Across Treatment Groups
The Dermatology Life Quality Index (DLQI) total score will be compared across the three predefined treatment groups. Total scores range from 0 to 30, with higher scores indicating greater impairment of dermatology-related quality of life.
Measured: Baseline (Day 1)
Pain Numeric Rating Scale (NRS) Score Across Treatment Groups
Pain intensity assessed using the Numeric Rating Scale (NRS) will be compared across the three predefined treatment groups. Scores range from 0 (no pain) to 10 (worst imaginable pain), with higher scores indicating greater pain intensity.
Measured: Baseline (Day 1)
Pruritus Numeric Rating Scale (NRS) Score Across Treatment Groups
Pruritus intensity assessed using the Numeric Rating Scale (NRS) will be compared across the three predefined treatment groups. Scores range from 0 (no itch) to 10 (worst imaginable itch), with higher scores indicating greater pruritus intensity.
Measured: Baseline (Day 1)
Douleur Neuropathique 4 Questions (DN4) Score Across Treatment Groups
The Douleur Neuropathique 4 Questions (DN4) total score will be compared across the three predefined treatment groups among participants who report pain and undergo DN4 assessment. Total scores range from 0 to 10, with higher scores indicating a greater number of neuropathic pain features. A score of 4 or higher indicates a positive screening result for neuropathic pain.
Measured: Baseline (Day 1)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Sep 2026
- Study start11 Jun 2026
- Primary completionDec 2026 (estimated)
- Study completionJan 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (4)Papers the sponsor has linked to this study.
- Other trials for Chronic Plaque-type PsoriasisStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Cross-sectional
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Istanbul Training and Research Hospital
- Sponsor type
- Other government
- Responsible party
- Principal investigator, Yasemin Dündar Şahin, Istanbul Training and Research Hospital
- Investigators
- Vildan Manav, Study chair, Istanbul Training and Research Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07844772
- Sponsor's protocol ID
- IstanbulTRH-DERM-PSO-SP-2026
- Status last verified
- Sep 2026
- First submitted
- 17 Sep 2026
- Last updated
- 28 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be shared because there is currently no predefined plan or ethical approval for sharing de-identified participant-level data with researchers outside the study team. Study findings will be reported in aggregate form in scientific outputs.
Publications
Kotewicz M, Krajewski PK, Jaworek AK, Szepietowski JC. Clinical Characteristics of Cutaneous Pain in Psoriasis. J Clin Med. 2024 Jun 20;13(12):3610. doi: 10.3390/jcm13123610.
PubMed 38930137Remrod C, Lonne-Rahm S, Nordlind K. Study of substance P and its receptor neurokinin-1 in psoriasis and their relation to chronic stress and pruritus. Arch Dermatol Res. 2007 May;299(2):85-91. doi: 10.1007/s00403-007-0745-x. Epub 2007 Mar 17.
PubMed 17370082Gao H, Fang Y, Zhang Y, Xie T, Chen Z, Wang G. Neuroimmune Crosstalk in Psoriasis: Mechanisms and Therapeutic Implications. Inflammation. 2025 Dec 22;49(1):14. doi: 10.1007/s10753-025-02385-3.
PubMed 41428266Koca TT, Gogebakan H, Nazik H, Cetin G, Ozturk P. Clinical Importance of Central Sensitization and Neuropathic Pain in The Treatment and Follow-Up of Patients with Psoriasis and Psoriatic Arthritis. Indian J Dermatol. 2026 Jan-Feb;71(1):58-64. doi: 10.4103/ijd.ijd_319_23. Epub 2025 Dec 31.
PubMed 41585820