Anaphylactic reaction to povidone secondary to drug ingestion in a young child.

Povidone (PVP, polyvinylpyrrolidone) is a mixture of synthetic polymers with molecular weights (between 10,000 and 70,000 Da) comparable to those of the plasma proteins. It is commonly used as an excipient in different pharmaceutical products; in artificial tears and contact lens preservation solutions; as an additive in foodstuffs (E-1202), serving as a support for edulcorants, and in food supplements in the form of tablets and pills; as an antiseptic (Betadine); and as a dispersant and stabiliser in hair sprays. Contact dermatitis associated to povidone--iodine is not rare, though immediate hypersensitivity reactions to this substance are unusual, with few cases of anaphylaxis documented in the literature. We present a case of anaphylactic reaction in a young boy. A boy aged four years and two months was seen for the study of asthma beginning at one and a half years of age. The patient had suffered an episode of asthma and rhinitis at the age of three years and 10 months, developing 1--2 h after receiving Estilsona (prednisolone oral solution), perioral and nasogenian swelling and erythema, and eye itching with conjunctival reddening. The condition lasted 4--6 h, and no other manifestations were described. The patient had taken this medication several times before without reactions. Initial exploration based on the prick test revealed the following: Dermatophagoides farinae and D. pteronyssinus 4+, grass pollen 2--3+, dog epithelia 3+, and cat dander 2--3+ (with respect to histamine). Estilsona (13.3 and 1.33 mg/ml of methylprednisolone stearate): 3 × 2 mm (2+), with histamine 4 × 3 mm. Budesonide suspension for nebulisation (250 g/ml) and methylprednisolone (solution for injections) 10 mg/ml and 1 mg/ml, negative. An open oral provocation test with the suspect drug (Estilsona) was performed: after a cumulative dose of 0.5 ml containing 6.65 mg of prednisolone stearate, equivalent to 3.5 mg of prednisolone (first 0.2 ml and then 0.3 ml after 30 min), and equivalent to a quarter of the therapeutic dose of prednisolone calculated as 1 mg/kg b.w., perioral erythema and wheals developed after 20 min. The dosage was repeated half an hour after the previous dose, and 10 min later the patient developed intense barking cough with mild dyspnoea, watery rhinorrhea, sneezing, some wheals on the face and arms, and inspiratory and expiratory wheezing. Intramuscular adrenalin was therefore administered, with inhalatory salbutamol, levocetirizine and a single dose of deflazacort via the oral route. Half an hour later the respiratory symptoms disappeared, while the nasal symptoms and urticaria were resolved after 2 h. One month later the study was amplified, testing all the components and excipients: