A vitamin D level of 37 ng/ml is generally considered within an adequate range, so calcium or vitamin D supplements like Shelcal may not be prescribed for deficiency alone. However, in this case, the patient has long-standing skin symptoms, erythroderma under evaluation, and other medical conditions, so the doctor may have prescribed it for supportive bone and calcium balance during illness, reduced sunlight exposure, or overall nutritional support. The need depends on the full clinical picture, not just vitamin D levels, so it is best to confirm the exact reason with the treating doctor rather than stopping or changing it on your own.