D1.76 - The Hot Chocolate Drink Dilemma

Introduction

Allergy to chocolate is rare. We present 2 unusual cases of allergy to hot chocolate drinks despite tolerance to confectionery chocolate.

Case 1 

A 76-year-old gentleman presented with 2 episodes of facial angioedema and breathlessness within 20 minutes after drinking a hot chocolate drink. He was treated with steroids, antihistamines and tranexamic acid on the first occasion and IM adrenaline on the second occasion. No tryptase deflection was detected on both occasions.

He has tolerated chocolate, dairy and nuts since his reactions.

Skin prick test (SPT) was positive (5x5mm) to hot chocolate powder mixed with saline. SIgE to cacao, C3 C4 were normal.

Case 2

A 37-year-old lady presented with 3 reactions involving hot chocolate product ingestion. During the first episode, within 15 minutes of eating a hot chocolate muffin, she developed a  macular pruritic rash on her chest and neck with mild lip swelling. During the second episode, she had a hot chocolate drink with some peanuts and 5 minutes later developed lip swelling and urticaria. For the third episode, she had a hot chocolate drink and 5 minutes later developed lip swelling, urticaria and felt faint. She attended A&E for all 3 episodes and was treated with antihistamines.

SPT to peanut and cacao were negative. SIgE to cacao, peanut and tree nuts were negative.

SPT and prick to prick test to various forms of confectionery chocolate (milk, white, dark) were negative/ borderline positive and she passed oral challenge to these confectionery chocolates. However, she had urticaria within minutes after drinking a hot chocolate drink. The patient was later brought back for further challenge. She tolerated chocolate powder mixed with cold water but developed urticaria with cooled chocolate drink (chocolate powder mixed with hot water and cooled).

Conclusion

These two cases demonstrated allergy to hot chocolate drink with tolerance to confectionery chocolate among 2 patients with no history of atopy and no prior occupational exposure to cocoa.

Possible hypotheses include (i) the specific manufacturing process of chocolate powder which leads to its allergenicity (demonstrated in both cases) and (ii) the unique property of heat which leads to an increased allergenicity of chocolate powder (demonstrated in the second case).