Background: Recurrent infection syndrome (RIS) results from repeated interactions between hosts and environmental infectious agents and is considered normal (NRIS) because of its benign evolution and positive effects in the development of normal immune responses. Abnormal RIS (ARIS) is characterized by the unusually high frequency of severe infections, either as a result of anatomical or functional abnormalities or due to primary or secondary immunodeficiencies (PIDs and SIDs, respectively). Recurrent mucocutaneous infections (MCIs) can be manifestations of RIS or ARIS and could bemore frequent in primary immunodeficiencies. Similarly, etiologic agents might vary from what is observed in the general population. Methods: We carried out a descriptive study to determine the prevalence of aerobic bacterial and fungal mucocutaneous infections in 452 patients with recurrent infections, using clinical records to establish immunological status associated with the presence and characteristics of the infections. Microbiological analyses from mucocutaneous lesions were used to confirm the etiology. Results: We found mucocutaneous infections in 50 patients for a total of 62 episodes (bacterial or fungal infections in 38 vs. 12 patients, respectively). Mucocutaneous infections were more frequent (21.8% vs. 9.1% ; OR=2.8) and recurrent (8.7% vs. 0.2% ; P=0.000) in primary immunodeficient patients. Furthermore, those with defects in phagocytic cells presented more mucocutaneous infections (56.2% ) than patients with other primary immunodeficiencies (11.3% ; OR=10.1). Conclusions: Bacterial and fungal mucocutaneous infections are more frequent and severe in primary immunodeficient patients, particularly those with defective phagocytosis. Early and adequate assessment of the nature of mucocutaneous infections in ARIS should impact the ability of physicians to treat promptly, avoid complications and reduce the costs of medical assistance. u001a Background: Recurrent infection syndrome (RIS) results from repeated interactions between hosts and environmental infectious agents and is considered normal (NRIS) because of its benign evolution and positive effects in the development of normal immune responses. Abnormal RIS (ARIS) is characterized by the unusually high frequency of severe infections, either as a result of anatomical or functional abnormalities or due to primary or secondary immunodeficiencies (PIDs and SIDs, respectively). Recurrent mucocutaneous infections (MCIs) can be manifestations of RIS or ARIS and could be more frequent in primary Methods: We carried out a descriptive study to determine the prevalence of aerobic bacterial and fungal mucocutaneous infections in 452 patients with recurrent infections, using clinical records to establish immunological status associated with the presence and characteristics o f the infections. Microbiological analyzes from mucocutaneous lesions were used to confirm the etiology. Results: We found mucocutaneous infections in 50 patients for a total of 62 episodes (bacterial or fungal infections in 38 vs. 12 patients, respectively). Mucocutaneous infections were more Those with defects in phagocytic cells presented more mucocutaneous infections (56.2%) than patients (21.8% vs. 9.1%; OR = 2.8) and recurrent (8.7% vs. 0.2% with other primary immunodeficiencies (11.3%; OR = 10.1). Conclusions: Bacterial and fungal mucocutaneous infections are more frequent and severe in primary immunodeficient patients, particularly those with defective phagocytosis. Early and adequate assessment of the nature of mucocutaneous infections in ARIS should impact the ability of physicians to treat promptly, avoid complications and reduce the costs of medical assistance.  u001a