Medication overuse headache is a secondary headache disorder that occurs in those with a primary headache disorder (commonly tension-type headache or migraine). This Primer reviews the epidemiology, pathophysiology, diagnosis and treatment of medication overuse headache, and discusses how this disorder affects the quality of life of patients.

The ichthyoses are a group of dermatological disorders characterized by generalized scaly, erythematous skin, accompanied by epidermal barrier function disruptions. This Primer by Gutiérrez-Cerrajero and colleagues summarizes the epidemiology, mechanisms, diagnosis and treatment of ichthyosis, and discusses patient quality of life and open research questions for this condition.

Hazardous drinking and alcohol use disorder are associated with substantial harms to both the individual and others. This Primer discusses the epidemiology, mechanisms, diagnosis and management of these disorders, and also summarizes screening, prevention and the quality of life issues faced by individuals with these disorders.

Burkitt lymphoma is an aggressive form of B cell lymphoma that can affect children and adults. Its research has been central in advancing haematopathology and cancer research. This Primer by Siebert and colleagues summarizes the epidemiology, mechanisms, diagnosis and treatment of this disorder, patient quality of life and open research questions.

Osteosarcoma is the most common primary malignant tumour of the bone. This Primer by Gorlick and colleagues summarizes the epidemiology, mechanisms, diagnosis and treatment of this disorder as well as the quality of life of patients and open research questions.

Myelodysplastic syndromes (MDS) are a group of blood cancers involving dysregulated haematopoiesis, which may progress to acute myeloid leukaemia. This Primer provides an overview of the epidemiology, diagnosis, pathogenesis and management of MDS.