A good communication between patient and provider has the aimto understand the patient’s problems, to establish and maintain acaring relation, and to inform about disease. The quality of communicationmay have an influence on different important aspects, suchas satisfaction and adherence to treatment.In this thesis, the overairching aim was to evaluate the effects ofthe communication between patient and provider, by comparing theirevaluation of either the health-related quality of life of patients, or theseverity of the disease.It was chosen to focus on oral and dermatological conditions, sinceskin and teeth are some of the most important components of the appearanceof a person, and conditions which affect them can have deeppsychosocial implications on patients’ life.Paper I concerns skin conditions. Dermatologists’ opinions on skinhealth-related quality of life and psychological problems in patientswere compared to the patients’ reports.Papers II and III concern oral conditions. The evaluation of oralhealth-related quality of life problems in patients by the caregivers wascompared to the evaluation given by patients.In Paper IV, about oral mucosal conditions, the comparison wasmade between the evaluation of the severity of the disease by patientsand providers.Paper I: as regards quality of life, physicians tended to overestimateimpairment in several conditions, particularly in alopecia. In many diagnosticcategories, an underestimation of the frequency of depressionand anxiety by dermatologists was observed. Paper II and III: the correlation between patients’ and caregivers’evaluation of oral health-related quality of life was low. In general, caregiverstended to overestimate the quality of life impairment of their patients,particularly for women, for elderly people, and for patients witha low number of teeth. The difference between patient and caregiverevaluation did not depend on the professional status of the caregiver(dentist or hygienist), nor on the clinics.Paper IV: in oral mucosal conditions, the agreement between patients’and providers’ evaluation of severity was very low. Physicians tended tounderestimate severity more in older than in younger patients, and inpatients with a higher quality of life impairment compared to the others.The underestimation by the physician was also positively associatedto psychological problems and the presence of alexithymia.This thesis showed a low agreement between patient and provider inthe evaluation of quality of life and psychological problems of patients,and of the disease severity, both in dental and dermatological conditions.The discrepancies were both in the direction of an underestimationand an overestimation by the caregiver.