- Background: There are no published large-scale epidemiologic studies regarding the prevalence of skin diseases in patients with selective immunoglobulin A (IgA) deficiency (sIgAD). The purpose of this study was to investigate the prevalence of dermatological diseases in patients with sIgAD. Methods: This retrospective matched case-control study was based on data from the Leumit Healthcare Services data base (approximately 725,000 residents of Israel), which was searched for all subjects aged ≥12 years who had undergone serum total IgA measurements during 2004-14 for any reason. The case group included subjects with sIgAD. The control A group was randomly sampled from those subjects in whom an IgA was drawn (n ≈ 725,000), with a ratio of 10 controls for every case (1:10). The control A group was randomly sampled from those subjects in whom an IgA was drawn (n = 104,729) and the control B group was randomly sampled from the full study population (n ≈ 725,000), with a ratio of 10 controls for every case (1:10). Comorbidity was compared between the study groups. Results: The sIgAD group was characterized: 1) By a higher prevalence of atopic dermatitis (AD) (16 [4.6 %]) than the control A group (76 [2.1 %]; p = 0.004 and the control B group (64 [1.9 %]; p = 0.002). 2) By higher prevalence of acne (69 [19.9 %]) than the control A group (516 [13.8 %]; p = 0.013) and control B group (494 [14.2 %]; p < 0.001). 3) By higher rate of chronic spontaneous urticaria (CSU) (17 [4.9 %)] than in the control A group (31 [0.9 %], with odds ratio 5.54 [3.04-10.13]; p < 0.001) and the control B group (28 [0.8 %]; p < 0.001). Conclusions: sIgAD is characterized by a higher prevalence of AD, CSU and acne.