P.L. Tong, E.T. Chow
We present the case of a 42-year-old woman with atopy
including eczema that had a 20-month history of a pruritic
erythematous rash commencing on the eyelids, which consequently
spread to involve the scalp and rest of her body.
Two separate biopsies were performed and the diagnosis
was provided as urticaria and urticarial dermatitis. She
was not able to tolerate topical corticosteroids or
pimecrolimus and developed a hypersensitivity reaction to
azathioprine. Her rash was however responsive to systemic
corticosteroids. As she was suspected of allergic contact
dermatitis, she was patch tested to the standard, cosmetic,
corticosteroid, sunscreen series, and photo-patch tested to
the sunscreen series. Her own products were tested which
included QV intensive moisturiser that contains isopropyl
myristate for which she was found to be highly reactive.
Isopropyl myristate is a solvent used in moisturisers, cleansing
products, perfumes, make-up, nail and hair care products
and topical medicaments. It is not in the Standard series
or True test. Although an uncommon allergen, it needs to be
tested in patients who are suspected of allergy to cosmetics
and skin care products as highlighted by this case.