Psoriasis and hidradenitis suppurativa are two common dermatological diseases that affect physical, social, and psychological aspects of the patients' lives. The aim of this study was to compare quality of life, depression, anxiety, self-esteem, and loneliness in patients with psoriasis and hidradenitis suppurativa. One hundred and eight patients with psoriasis, 113 patients with hidradenitis suppurativa and 116 healthy controls were included in the study. The quality of life, depression, anxiety, and loneliness of the patients as well as their self-esteem were assessed using the Dermatology Life Quality Index (DLQI), Hospital Anxiety and Depression Scale (HADS), the UCLA loneliness Scale (UCLA-Version 3) and the Rosenberg's Self-esteem Scale (RSES), respectively. Patients with psoriasis (12.77±4.43) reported a higher mean impairment in DLQI than patients with hidradenitis suppurativa (11.10±6.53, P=0.028), in the univariate comparisons. Patients with psoriasis presented statistically significantly higher levels of anxiety and depression than both patients with hidradenitis suppurativa and healthy controls, while patients with hidradenitis suppurativa also had higher anxiety and depression compared with healthy controls. Patients with psoriasis (46.31±6.36) reported statistically significantly higher loneliness than both patients with hidradenitis suppurativa (43.18±7.40) and controls (40.42±4.41), while the patients with hidradenitis suppurativa also presented higher loneliness in comparison with controls. Lower levels of self-esteem were found in patients with psoriasis (15.08±3.11) compared with both patients with hidradenitis suppurativa (18.89±1.69) and controls (20.25±2.60), while patients with hidradenitis suppurativa also had lower self-esteem than controls. Significant levels of depression, anxiety, and impaired quality of life were strongly associated with disease severity. When patients with mild disease were compared, those with psoriasis presented with both higher levers of loneliness and lower scores for quality of life. Although both psoriasis and hidradenitis suppurativa are associated with impaired quality of life and psychological aspects, significantly worse scores were recorded in patients with psoriasis.