Serum levels of parathyroid hormone and parathyroid-related peptide in psoriasis.

Psoriasis is a common skin disorder that may be triggered by hormonal disturbances, among other factors. Some studies have demonstrated an elevation of serum parathyroid hormone (PTH) levels in psoriasis and several other diseases of keratinization of unknown aetiology. PTH-related peptide (PTH-rp), on the other hand, is a potent inhibitor of epidermal cell growth factor and is not expressed in psoriatic skin. Serum levels of this peptide have not been reported in psoriasis. Immunoassay was used to measure serum PTH and PTH-rp in 22 patients with plaque-type psoriasis before and after treatment with mometasone furoate. Results were compared with a group of 20 healthy, non-psoriatic volunteers. Serum PTH levels were significantly elevated in the psoriatic group compared with the control group (p=0.001) and were significantly reduced after treatment (p=0.01). A correlation was found between pretreatment serum PTH levels and psoriasis area and severity scores (PASI) (r=0.42; p=0.01). In contrast, serum PTH-rp levels were not different between psoriatics and controls and were not affected by treatment. These findings indicate that serum PTH concentrations reflect disease activity in patients with psoriasis.