What condition is correlated with pitting on fingernails observed in a child?

Pitting on fingernails is most commonly associated with psoriasis, particularly in cases where the skin condition is prevalent in children. Psoriasis is an autoimmune disorder that manifests as flaky, silvery patches on the skin and can also affect the nails. The pitting occurs due to the inflammation that disrupts the normal production of keratin, leading to small depressions on the nail surface.

In children, this correlation is particularly important as early recognition of nail changes can lead to prompt diagnosis and management of underlying skin conditions. While other conditions such as iron-deficiency anemia, onychomycosis, and vitamin C deficiency can lead to various nail changes, they are not typically associated with pitting. Iron-deficiency anemia may lead to spoon-shaped nails, onychomycosis commonly results in thickened and discolored nails, and vitamin C deficiency can cause splinter hemorrhages but does not lead to pitting. Thus, the characteristic pitting seen in a child's fingernails points strongly toward psoriasis.