Can wearing a wet swimsuit cause infections? Here’s what to do

Intimate personal hygiene involves, in addition to normal daily cleansing, the use of clean underwear, preferably made from neutral materials such as cotton and free from dyes. Indeed, certain materials (particularly synthetic ones) can cause irritation or even skin allergies, and this risk is slightly higher in an area such as the genital region, which is particularly sensitive. There are therefore certain habits that can contribute to skin problems and even infections, such as genital and urinary tract infections, which, as we know, are particularly troublesome (and in some cases even dangerous to health). One of the most common concerns is whether wearing a swimsuit for long periods can cause (or contribute to) genital infections, such as thrush, or urinary tract infections, such as cystitis, as well as the more serious pyelonephritis.

As we know, environmental conditions can either promote or inhibit the growth of bacteria and fungi (as well as viruses). This is why using hot water to wash certain items of clothing or freezing food helps to prevent bacterial growth: temperature and ambient humidity influence the proliferation of microorganisms. This also happens within our bodies. A favourable ‘environmental’ situation can cause an existing infection to spread. Obviously, it cannot cause the infection itself – infections are caused by bacteria, viruses or fungi present in the environment – but conditions such as heat or humidity can promote the growth and development of microorganisms such as Candida (which frequently causes genital thrush) or Enterococci and Staphylococci. Swimwear is almost always worn in summer, so environmental conditions are characterised by high temperatures. This alone can lead to the growth of microorganisms. But this is not the only factor. In summer, people sweat a great deal, and the heat associated with sweat (which consists of fluids and salts) further encourages the growth of unwanted microorganisms. It is now a well-established and well-researched fact that varying levels of heat and temperature can encourage the proliferation of microorganisms: research laboratories are well aware of this, and indeed use these very environmental variations to study the development of viruses, bacteria and fungi.

Swimwear acts a bit like an ‘incubator’: it is soaked with water and sweat, creating a very damp environment that maintains a high temperature; it is ‘contaminated’ with salts and other substances, and so prolonged contact with the skin tends to encourage the growth of fungi and bacteria. We know, for example, that 60 per cent humidity can kill 50 per cent of Candida spores, but this takes 3–5 days; for this reason, maintaining a warm, humid environment—even for just a few hours—can encourage the growth of microorganisms. High temperatures are also among the causes of an increase in urinary tract infections.

These infections are generally harmless and short-lived, but sometimes – particularly in susceptible individuals or those with weakened immune systems – they can become aggressive and very troublesome, and in rare cases even harmful. Bacterial genital infections, such as those caused by streptococci, can lead to dermatitis, folliculitis and vaginitis. Fungal infections, such as those caused by Candida, can result in candidiasis, which can sometimes be extremely troublesome and difficult to treat. Viral infections are rarely noticed but are often the result of pre-existing infections that have ‘flared up’ due to specific circumstances. The genital and urinary tracts are in close contact both anatomically (they are ‘close’ to one another; in women, they are even located in the same region) and biologically, and many microorganisms that cause problems in the genital tract also proliferate very well in the urinary tract. It is no coincidence that many urinary tract infections subsequently become genital infections, and vice versa. We should also bear in mind that seawater is not sterile and, to varying degrees depending on the area, may contain many microorganisms, some of which are known (for example, Escherichia coli) to cause genital and urinary tract infections.

Of course, as well as maintaining good personal hygiene, you should avoid wearing a swimsuit for many hours at a time, especially if it is wet. Rinse or wash your swimwear frequently to remove salt, sea water and debris. Change your swimwear several times throughout the day and, if possible, take frequent showers with fresh water. Of course, a day at the beach shouldn’t be seen as a risk, but it’s wise to take the necessary precautions and use common sense. In general, too, if you are suffering from an acute genital or urinary tract infection, it is best to avoid swimming in the sea, as this could make the problem worse. Obviously, you should also follow any appropriate treatment prescribed by your doctor.