Objective: Many causes such as allergic diseases (ADs), systemic diseases (SDs), dermatologic diseases (DDs), infections, cancers, dry skin, psychological problems, and aging can cause pruritus. We aimed to determine the diagnoses of patients who were referred to our clinic from other specialties because of pruritus.

Materials and Methods: Sociodemographic characteristics, clinical features, blood, urine, stool and skin prick test (SPT) results of all patients presenting to our allergy and clinical immunology clinics with isolated pruritus between 2021 and 2024 were retrospectively evaluated.

Results: A total of 18,695 patients were examined between 2021 and 2024: 276 patients had isolated pruritus, 75 of whom had acute pruritus (AP) and 201 had chronic pruritus (CP). The median (min-max) age was 33 (18-81) years and 43 (18-97) years in patients with AP and CP, respectively.

Infection and drug-related pruritus were more frequent in patients with AP (p=0.002, p=0.001), and the frequency of CP was higher in patients with pruritus increased by inhaled allergens (p=0.001). Leukocyturia was more frequent in patients with CP compared to those with AP (p=0.018), and SPT positivity and low ferritin were more frequent in patients with CP (p=0.004, p=0.045).

The most common cause in the study population was ADs (n=77, 28%), followed by SDs (n=74, 27%). The frequency of DDs (n=24, 32%) and SDs (n=16, 21%) was higher in patients with AP, whereas ADs (n=62, 31%) and SDs (n=58, 29%) were more common in patients with CP.

Iron deficiency anemia (IDA) was the most common SD (n=41, 55%), followed by thyroid disease (n=14, 19%). The most common DD was dry skin (n=31, 46%), followed by scabies (n=28, 41%).

Conclusion: Pruritus is an important problem for both patients and physicians. When pruritus is mentioned by physicians, ADs come to mind first. However, SDs, especially IDA, should not be forgotten.