Fig. 1

Part of the DermO ontology. The ontology classifies cutaneous diseases by etiology, anatomical location/cell type, and phenotype consistent with current clinical practice, and uses polyhierarchy (multiple parents) to maximize the types of knowledge captured by the ontology. The figure shows the path up the hierarchy for the classification of, neutrophilic cicatricial alopecia, with parent terms outlined in red and with a red arrow connecting parents and children. Multiple types of classification allow for multiple entry points and views of diseases. For example Psoriasis is a child of “papulosquamous disorder”, “inflammatory dermatoses”, and “causes of secondary erythroderma”. Most of the relations shown here are “is_a” – ie the child is a “type-of” its parent. Note that not all of the terms in this region of the ontology are shown here, for clarity