7th August 2020

A mother presents with her 9-year-old son, she says he has been constantly itching his elbows and shoulders

A mother presents with her 9-year-old son, she says he has been constantly itching his elbows and shoulders, over the last few weeks. On examination the patient has red, raised patches, with a few blisters over his elbows and shoulders. On further questioning, his mother says he is quite small compared to his peers at school and that he sometimes complains of a tummy ache after dinner. 

What investigation will definitively confirm the likely underlying diagnosis? 

Select the SINGLE most appropriate option from the list below. Select ONE option only.