Human alpha-fucosidase (EC 3.2.1.51) is an enzyme (hydrolase) of particular biological and medical interest, as the inherited deficiency in its activity leads to fucosidosis, a pathology belonging to severe glycoprotein lysosomal storage disorders. Although its importance has increased in latest years, data about its plasma level in children with inflammatory disorders are still lacking. In the present study, plasma activity of alpha-L-fucosidase-1 (FUCA-1) and its potential association with chronic inflammatory pathologies was evaluated in hospitalized individuals, both pediatric and adult ones. A number of 201 Hungarian hospitalized patients, 144 children (1-13 years) and 57 adults (31-88 years), were enrolled in the study and underwent plasma assay of FUCA-1 activity, following the normal routine analytical run in the hospital service. Regression and Pearson tests were evaluated to investigate the relationship between FUCA-1 plasma levels and inflammatory disorders diagnosed with subjects recruited in the study. No correlation of FUCA-1 activity was observed in the pediatric patients with immune (p = 0.9677) or metabolic (p = 0.6974) disorders, but a correlation was reported when comparing clusters of chronic inflammatory and autoimmune disease vs. controls (p < 0.05). Furthermore, a relationship was found between FUCA-1 activity in plasma and inflammatory disorders and autoimmunity both in adults and in the pediatric cohort of patients (Pearson test, p = 0.000148). Alterations in plasma levels of FUCA-1 were significantly associated with chronic inflammatory and autoimmune disorders, both in children and adults. The result of the present study should encourage further research on FUCA-1 as a marker of chronic inflammation and autoimmunity.