Hypercalcemia in Poorly Controlled Psoriatic Arthritis
Hypercalcemia is not a recognized feature of poorly controlled psoriatic arthritis; in fact, the opposite is true—psoriatic arthritis is associated with hypocalcemia and abnormal calcium metabolism that promotes osteoporosis, not elevated calcium levels. 1, 2
Evidence Against Hypercalcemia in Psoriatic Arthritis
Calcium Abnormalities in Psoriatic Arthritis
Clinical studies demonstrate that psoriatic arthritis patients exhibit abnormal levels of total and ionized blood calcium, but these abnormalities manifest as hypocalcemia rather than hypercalcemia. 1
In a case-control study of 98 hospitalized psoriasis patients, 37.2% were hypocalcemic and 63.7% had normal serum calcium—notably, there was no hypercalcemia detected in any patient. 2
The imbalance of calcitropic hormones (parathyroid hormone and calcitonin) and abnormal calcium metabolism in psoriatic arthritis specifically promote the development of osteoporosis, not hypercalcemia. 1
Bone Mineral Density Findings
Patients with psoriatic arthritis demonstrate reduced bone mineral density, with 50% showing osteopenia and 5% showing osteoporosis in the arthritic group, compared to 27.5% osteopenia in non-arthritic psoriasis patients. 3
The duration of arthritis in psoriatic arthritis patients correlates negatively with bone mineral density values of the lumbar spine and total femur, indicating progressive demineralization with longer disease duration. 3
Serum calcium, phosphorus, and alkaline phosphatase levels show no significant elevation in psoriatic arthritis patients compared to non-arthritic psoriasis patients. 3
Critical Distinction: When Hypercalcemia Occurs with Arthritis
Hypercalcemia from Other Causes
If hypercalcemia is present in a patient with inflammatory arthritis, a complete evaluation for alternative causes is mandatory—including primary hyperparathyroidism, malignancy, sarcoidosis, or calcium pyrophosphate deposition disease (CPPD). 4
Hypercalcemia in the setting of acute inflammatory arthropathy should prompt investigation for CPPD, which is associated with metabolic disorders such as hyperparathyroidism, not psoriatic arthritis itself. 4
The presence of hypercalcemia with arthropathy requires measurement of intact parathyroid hormone (iPTH), parathyroid hormone-related protein (PTHrP), 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, calcium, albumin, magnesium, and phosphorus to determine the underlying cause. 5
Clinical Implications
Disease Heterogeneity
Psoriatic arthritis is a complex inflammatory disease with heterogeneous clinical features, but hypercalcemia is not among the recognized manifestations. 6
There may be little or no relationship between severity of musculoskeletal inflammation and severity of skin or nail psoriasis in PsA, but calcium abnormalities consistently trend toward hypocalcemia when present. 6
Monitoring Recommendations
Psoriatic arthritis patients with longer duration of joint disease are at risk for osteoporosis and may require preventative treatment efforts, including calcium supplementation rather than calcium restriction. 3
Hypocalcemia is a risk factor in psoriasis patients, and dietary calcium intake (dairy products) should be encouraged rather than restricted. 2