D1.78 - Non-Allergic Dermatologic Diagnoses Among Patients Presenting to an Allergy Immunology Outpatient Clinic: A Prospective Clinical Study

Patients frequently present to allergy immunology clinics with cutaneous complaints attributed to self-perceived allergic conditions. However, a substantial proportion of these cases may represent non-allergic dermatologic diseases. This study aimed to evaluate the demographic and clinical characteristics of patients attending a tertiary immunology and allergy clinic who were ultimately diagnosed with non-allergic dermatologic disorders.

In this prospective study, patients presenting to our immunology and allergy outpatient clinic between June 1 and December 31, 2025, who received a non-allergic dermatologic diagnosis were included. Initial clinical evaluation was performed in the immunology and allergy clinic, and selected cases requiring diagnostic clarification were assessed in collaboration with dermatology department. Demographic data, symptom characteristics, and duration, prior dermatology applications, and final diagnoses were recorded.

A total of 218 adult patients with non-allergic dermatologic conditions presenting to our tertiary allergy immunology clinic were included. The median age was 45 years. Females comprised 68.3% of the cohort. Educational attainment was distributed as 36.7% primary school, 28.9% high school, and 34.4% university graduates. The median symptom duration was 10.5 months, with 57.8% reporting symptoms lasting more than three months. Prior dermatology clinic consultation was reported by 136 patients (62.4%). Regarding allergy-related beliefs, 49.5% reported nonspecific or unspecified allergy suspicion, 22.5% suspected food allergy, 9.6% suspected drug allergy, and 18.4% reported no allergy belief. 

Pruritus was the most commonly reported symptom (83.9%), followed by localized skin redness (39.0%) and skin erosions (24.8%). Dermatologic examination revealed erythema in 56.0% of patients, xerosis in 47.2%, and papules in 41.3%, with less frequent findings including excoriation, scaling, pustules, plaques, crusts, telangiectasia, macules, vesicles, petechiae/purpura, and bullae.

Xerosis cutis was the most common diagnosis (26.6%), followed by insect bite reactions (10.6%), prurigo simplex (8.3%), seborrheic dermatitis (6.4%), acne vulgaris (6.0%), and rosacea (6.0%). Diagnosis was established clinically in all patients, with histopathology performed in 24 cases (11%) and laboratory investigations in 3 cases (1.4%) as needed.

Allergy-related beliefs were not significantly associated with age, sex, educational status, or symptom duration. Similarly, previous dermatology clinic application did not differ by sex or educational level, although patients aged 45–64 had higher rates of previous dermatology visits compared with younger adults (p=0.029). Symptom duration was strongly associated with previous dermatology clinic application: 5.3% of patients with symptoms <1 month had prior visits, compared with 45.2% of those with 1–3 months and 81.0% of those with >3 months (p<0.001). No association was observed between allergy-related beliefs and previous dermatology visits.

Non-allergic dermatologic conditions are common among patients with a self-perceived allergic dermatologic conditions presenting to immunology and allergy clinics. Improved triage, interdisciplinary collaboration, and public education may reduce misinterpretation and unnecessary healthcare utilization.