Case Presentation
A 23-year-old female with a recent diagnosis of hyperthyroidism
presented to her GP with an urticarial rash localised to her neck. She
was prescribed a course of cetirizine and prednisolone. Shortly after,
she presented to the emergency department with a spreading urticarial
rash extending to her neck, stomach, chest, back, genitals, upper and
lower legs, consisting of “extensive excoriations and dermatographia,
with blanching and wheals” (figures 1 & 2 ). She had given birth
to her first child as recently as four months ago and the only other
medication she took on a regular basis was carbimazole, which was
started one month prior to her presentation.
Investigations revealed normal inflammatory markers (CRP 2 mg/L ,
WBC 9.3 x 109/L ) and her renal & liver
function tests all remained within normal limits. No clinical findings
were evident on examination of her chest and abdomen and no focal
neurology was elicited. Her FT4 two weeks prior to admission was 38.4pmol/l, with a TSH of 0.01 mU/l , although her FT4 on the
day of admission was normal at 10.7 pmol/l . She was treated with
intravenous chlorphenamine in the emergency department then admitted for
observation and referred to the endocrinologist.
Over the next 48 hours she had a further exacerbation of her rash which
now resulted in lip swelling and she was started on intravenous
hydrocortisone and oral loratadine. Her carbimazole was stopped due to
concerns it may be the cause of the rash. She was reviewed the next day
and an urgent dermatology opinion was sought, whilst a full autoimmune
screen was sent (all negative, see table 1). Urinalysis was also
negative. Thyroid peroxidase antibody (anti-TPO) levels were raised at
> 1000 iU/mL.
After dermatology review the patient was started on oral chlorphenamine
(at triple the normal licensed dose), topical menthol 1% cream and her
steroid dose was gradually reduced. After five days of treatment her
urticaria was limited to her legs and scalp, and she had symptomatically
improved.