Ho and thanks for the query, With the clinical syndrome you describe, it might be very easy to make an easy clear cut difference whether it is psoriatic, allergic or the direct connection to food cannot be established. However, more information is required to make a diagnosis. Any family history of these symptoms, history of allergies, any joint pains or generalized feeling of malaise. A clinical evaluation and laboratory tests could make the difference. Measuring IgE levels in blood if raised coul dbe indicative of the allergic component. Specific rheumatologic tests could indicate psoriaos. You need to book an appointment with your dermatologist first. thanks and best regards, Luchuo, MD.