Effects of Isotretinoin on Smell

Isotretinoin is a common medicine used to treat moderate to severe acne. It often causes dryness of the skin and the inside of the nose. Because a normal sense of smell depends on a healthy nasal lining, this dryness may affect how well a person can smell. This study will examine whether isotretinoin treatment changes the sense of smell in adults with acne. Before starting isotretinoin, participants will complete a standardized smell test and two short questionnaires about nasal symptoms and quality of life: the Nasal Obstruction Symptom Evaluation (NOSE) scale and the 22-item Sino-Nasal Outcome Test (SNOT-22). After at least 4 weeks of treatment, the same smell test and questionnaires will be repeated. By comparing results before and after treatment, the study will test the hypothesis that isotretinoin has a negative effect on olfactory function and may reduce patients' ability to smell.

Inclusion Criteria: * Diagnosed with acne and scheduled to start oral isotretinoin as part of routine dermatology care * Willing to participate and able to give informed consent * Not currently smoking * No history of allergic rhinitis, sinusitis, or active upper respiratory infection * No medical condition known to affect the sense of smell Exclusion Criteria: * Younger than 18 years or older than 45 years * Current cigarette smoking * History of chronic sinonasal disease * Any condition that would prevent completing the smell test * Not willing to continue participation or withdrawal of consent at any time