Characteristics of NFD can include red or dark patches on the skin; burning, itching, swelling, hardening, and tightening of the skin; yellow spots on the whites of the eyes; joint stiffness with trouble moving or straightening the arms, hands, legs, or feet; pain deep in the hip bones or ribs; and muscle weakness. Patients develop large areas of hardened skin with fibrotic nodules and plaques. Flexion contractures with an accompanying limitation of range of motion can also occur. NFD resembles scleromyxedema at the histologic (microscopic) level; it shows a proliferation of dermal fibroblasts and dendritic cells, thickened collagen bundles, increased elastic fibers, and deposits of mucin.