Thulja is a Paediatrician and Allergologist, and one of a handful of fully accredited allergy specialists on the African continent. She holds a sub-specialty Certificate in Paediatric Allergy, Diploma in Allergy, and the Union of European Medical Specialists Allergy and Immunology Certificate. She is currently a consultant at the University of Cape Town Lung Institute, where she is actively involved in research in the field of paediatrics, allergy, and immunology and has co-authored. several publications in international peer review journals.

Thulja is currently serves on the boards of the European Academy of Allergy and Clinical Immunology, and the World Allergy Organization, and is also involved in several international Task Force Groups.