The goal of this observational study is to learn about microvascular changes and hair follicle activity in patients with alopecia areata. The main questions it aims to answer are:

Do blood levels of markers related to blood vessel formation (VEGF-A) and inflammation (VCAM-1) differ between patients with alopecia areata and healthy individuals?

Is there a link between these blood markers and structural changes in the nailfold capillaries?

How do these markers relate to specific trichoscopic signs of disease activity (such as black dots or exclamation mark hairs) and the overall severity of hair loss (SALT score)?

Researchers will compare patients with alopecia areata (grouped by disease duration: acute <6 months vs. chronic >6 months) to healthy volunteers to see if there is a significant difference in systemic and local vascular indicators.

Participants will:

Undergo a trichoscopic scalp examination to identify markers of disease activity (black dots, yellow dots, exclamation mark hairs) and calculate the SALT score.

Have their nailfolds examined with a digital capillaroscope (50x) to detect microvascular alterations.

Provide a blood sample to measure the levels of VEGF-A and VCAM-1.

Alopecia areata (AA) is a common autoimmune form of non-scarring hair loss. Although the exact cause is unknown, it is thought that inflammation and changes in the microvasculature (small blood vessels) play a significant role. This study aims to investigate the systemic and local vascular components of the disease.

The study includes 60 patients diagnosed with alopecia areata and 30 age- and sex-matched healthy volunteers. Patients are categorized into two groups based on disease duration:

Acute Group: Patients with a disease duration of less than 6 months.

Chronic Group: Patients with a disease duration of 6 months or longer.

Methodology and Procedures:

Dermatological and Trichoscopic Examination: All patients undergo a clinical examination using a Dermlite 5 dermatoscope. The severity of hair loss is calculated using the SALT (Severity of Alopecia Tool) score. Trichoscopic markers of disease activity, including black dots, yellow dots, exclamation mark hairs, broken hairs, vellus hairs, and pigtail hairs, are recorded according to Rudnicka's criteria.

Nailfold Capillaroscopy: To evaluate local microvascular alterations, nailfold capillaroscopy is performed using a Dino-Lite digital microscope (50x magnification). Examinations are conducted on the 2nd to 5th fingers of both hands after a 15-minute acclimatization period in a temperature-controlled room (20-23 °C). Morphological changes such as capillary dilatation, tortuosity, hemorrhages, and avascular areas are documented. An "abnormal pattern" is defined as the presence of two or more abnormalities in at least two fingers.

Biochemical Analysis: Venous blood samples are collected from all participants. After centrifugation, serum is separated and stored at -80 °C. Serum levels of Vascular Endothelial Growth Factor A (VEGF-A) and Vascular Cell Adhesion Molecule 1 (VCAM-1) are measured using the ELISA method.

The study will analyze the correlation between these biochemical markers, trichoscopic activity signs, and capillaroscopic findings to better understand the vascular pathogenesis of alopecia areata across different disease stages.

Inclusion Criteria:

• Age: Participants aged between 18 and 60 years.
• Diagnosis: Clinical and trichoscopic diagnosis of Alopecia Areata (AA) by a dermatologist.
• Categorization: "Acute" (<6 months duration) or "Chronic" (≥6 months duration) groups.
• Consent: Ability to provide written informed consent for participation in the study.

Exclusion Criteria:

• Medical History: Patients with a history of diabetes mellitus, autoimmune diseases, connective tissue diseases, chronic inflammatory or vascular diseases.
• Pregnancy & Lactation: Pregnancy or breastfeeding.
• Lifestyle Factors: Active smoking or chronic alcohol use.
• Hair & Nail Conditions: Causes of hair loss other than alopecia areata, the presence of any nail disease, or having had a manicure within the last 3 weeks.

The study population consists of patients diagnosed with Alopecia Areata (AA) and healthy volunteers recruited from Istanbul Education and Research Hospital, a tertiary care dermatology outpatient clinic in Istanbul. The patient group is stratified into acute and chronic phenotypes based on disease duration. The healthy control group includes age- and sex-matched individuals with no history of hair, nail, or systemic vascular diseases.