Porous skeletal lesions (PSL) have been reported in scientific literature since the 19th century, yet their etiology(ies) remains a complex issue under debate. The aim of this study is twofold: evaluate the frequency, co-occurrence, and association of PSL with biological sex and age at death and examine possible relationships between the presence/absence of PSL with the known cause of death (COD). Fifty-six non-adult skeletons from the Coimbra Identified Skeletal Collection (19th to 20th centuries) were evaluated. Lesion presence/absence was recorded macroscopically without previous knowledge of the biographic data. Forty-nine individuals (87.5%) presented at least one type of PSL, and cribra femoralis was the most frequent (n = 39), followed by orbitalia (n = 26), humeralis (n = 15), and cranii (n = 6). Porous skeletal lesions affected males and females equally, and younger individuals presented a significantly higher frequency of cribra femoralis. Even without statistical significance, the cooccurrence of cribra orbitalia, humeralis, and femoralis was common, as described in the "cribrous syndrome" where it is advocated a shared etiology for these lesions, based on macroscopic, microscopic, and radiological features. Individuals with a COD as respiratory infection, particularly pulmonary tuberculosis, exhibited a higher risk of expressing cribra orbitalia. The results of this investigation suggest an influence of age and infectious diseases in the expression of PSL, impacting the bioarchaeological interpretations. There is a need for further research in clinical, autopsy, and identified skeletal collection samples to further understand co-occurrence, comorbidity, and possible frailty related to PSL.