Fungal diseases in humans can be difficult to treat in part because the drugs used can also cause damage to human cells.

Fungal diseases in humans indeed present a significant challenge in treatment. This is primarily due to the similarity between fungal cells and human cells, which makes it difficult to target the fungi without harming human tissues. Here are some key points to consider:

1. Cell Structure Similarity: Both fungi and human cells are eukaryotic, meaning they share similar cellular structures and metabolic pathways. This similarity complicates the development of antifungal drugs that selectively target fungal cells.

2. Drug Mechanisms: Most antifungal medications target specific components of fungal cells, such as ergosterol (a key component of the fungal cell membrane) or enzymes involved in cell wall synthesis. However, the similarities in human cell membranes can also lead to side effects.

3. Resistance Issues: Some fungal strains have developed resistance to commonly used antifungal drugs, making the treatment even more complicated. This resistance can be due to overuse or inappropriate use of antifungal agents.

4. Patient Variability: Individual patient factors, such as immune status, age, and the presence of other health conditions, can also influence the effectiveness of antifungal therapies and the potential for adverse reactions.

5. Development of New Drugs: Ongoing research is focused on developing new antifungal agents with more specific mechanisms of action or those that can bypass the resistance mechanisms that fungi develop.

In summary, the treatment of fungal diseases in humans is complex due to the similarities at the cellular level, the development of drug resistance, and patient variability, making it crucial to carefully consider the choice of antifungal agent.