Endocrine Abstracts

Case history: We present a 44 year old female with persistent severe burning itchy rash over the face, scalp and upper body for ten months. She was reviewed in multiple dermatology clinics and a diagnosis of chronic urticaria was made. Despite various treatments including antihistamines and steroids, symptoms persisted affecting her quality of life significantly.

Investigations and diagnosis: Routine blood investigations revealed mild persistent elevated calcium up to 2.75 mmol/l (NR: 2.15–2.55) and she was referred to the Endocrine clinic. Further investigations showed inappropriately normal parathyroid hormone level of 5.6 pmol/l (NR: 1.6–6.9). 24 h urinary calcium was elevated 8.05 mmol/24 h (NR: 2.5–7.5). Serum electrophoresis, ACE, LDH and immunoglobulins were within normal limits. Sestamibi scan was negative for parathyroid adenoma. US parathyroids revealed right inferior parathyroid adenoma. She underwent parathyroidectomy followed by immediate resolution of symptoms. Histology confirmed parathyroid adenoma. She continued to remain symptom free when reviewed in clinic six weeks later.

Conclusion and points for discussion: Primary hyperparathyroidism is a rare cause of chronic refractory urticaria. Literature review shows less than six reported cases so far. Antibodies to calcium sensing receptor genes might be postulated in some cases. IgE receptor antibodies may also play a role, although there is no clear evidence linking these autoimmune mechanisms or autoantibodies to primary hyperparathyroidism. In conclusion, it is worth checking serum calcium and parathyroid hormone levels as part of work-up for refractory urticaria.