It is easy to pick up fungus!– they are particularly common on the floors of communal showers and changing rooms – and many of us probably already have fungi on our skin. They cause problems only when the conditions are right for them to thrive, which means warmth and moisture. When human beings started wearing enclosed shoes, which trap sweat and heat, we created ideal conditions for fungi. This is why only 1% of people in Zaire, Africa, have fungal toenail infections compared with 10% of people in the UK. It is not surprising that fungal toenail infections (and also athlete’s foot) are five times as common in people who have to wear work boots for long periods in wet conditions.
The fungi shelter under the tip of the nail and start to get a hold. This is particularly likely to happen if:
the end of the nail has been damaged (for example, by ill-fitting shoes) and is already slightly separated from its toe
you are taking long-term tetracycline medication and then expose your toenails to sunlight – this is called photo-onycholysis
you have a condition such as diabetes or an immune deficiency
you are elderly
the fungus is already multiplying between the toes (athlete’s foot).
The fungus very gradually spreads towards the base of the nail and down the sides, loosening the nail from the underlying toe and filling the separated area with crumbly, yellowish-white gunk. The nail itself becomes thicker and yellowish brown in colour. This can take months or years.
Sometimes the infection starts at the base of the nail, giving a whitish area near the half moon, or it may just affect the surface of the middle of the nail, where it will appear as a white patch.