1. Infections: Bacterial, viral, fungal, or parasitic infections.
2. **Inflammatory conditions**: Such as rheumatoid arthritis or lupus.
3. **Medications**: Some drugs, such as antibiotics and antihistamines, can cause fever.
4. **Heat exhaustion**: Overheating of the body due to external conditions.
5. **Malignancies**: Certain cancers can cause fever.
6. **Autoimmune diseases**: Conditions where the immune system attacks the body’s own tissues.