Introduction

Hyperhidrosis is the term used for excessive sweating.¹ It is not an uncommon condition, and can present in two forms: primary and secondary hyperhidrosis. Primary hyperhidrosis is mostly genetic, and changes progressively during puberty.² It is thought to link to a problem within the nervous system.¹ Secondary hyperhidrosis often occurs due to existing conditions such as chronic alcoholism, gout and spinal cord injury.²

In a case of hyperhidrosis, as many as 4 million sweat glands may be overactive.²⁰ In 2016, hyperhidrosis was identified as a condition that may have been of higher prevalence and severity than people would assume. Hence, talking about this topic helps to raise awareness, address key points, and provide valuable information.³

The term ‘febrile’ refers to the appearance of fevers causing, or related to, a certain illness.^4,5 This may occur via infection (for example, through a virus or bacteria).^6,7 Several infections have the capability to induce a fever.⁷ Do keep in mind that body temperature does differ between individuals.⁸ For example, women, on average, have higher body temperatures than men.11 It can also vary throughout the day, tending to be at its lowest during early hours.⁹ Febrile temperatures are usually recorded as such when above 37.5°C.¹⁰

Mechanisms of sweating in febrile illnesses

Physiological response to fever

Fever involves an abnormal increase in temperature.⁸ Our body temperature is largely regulated by the hypothalamus,¹² which is a small part of the ventral region in the brain.¹³ The hypothalamus is the body’s thermostat⁸; under normal conditions, the temperature will be kept within the normal range. However, in the event of infection, the reaction may involve a temperature rise due to the release of substances known as prostaglandins.¹² Prostaglandin synthesis is stimulated by pyrogens, and so pyrogens are thought of as being fever-producing.¹⁴ In order to combat the effects of fever, sweat glands are activated via the nervous system to induce sweating; the increase in body temperature acts as a thermal stimulus.¹⁵ These glands are located under the skin and produce water and salts. The cooling effect of sweating occurs via the evaporation of water from the skin.¹⁶

Hyperhidrosis during fever

Although sweating in the case of a febrile condition is useful for lowering body temperature, hyperhidrosis is, as described earlier, excessive sweating. It can be primary (e.g. genetic)² or can signal an underlying problem (secondary hyperhidrosis),¹⁷ but it can also be exacerbated by the heat induced by the body’s response to fever.18 It is not necessarily initiated by increased temperature, but heat is one of the triggers.¹⁹

Impact of hyperhidrosis on febrile illnesses

Excessive sweating, particularly when someone is undergoing a febrile condition, can present further complications. Hyperhidrosis means sweat glands are overactive, producing a lot of water. This loss of fluid from the body can cause dehydration. The symptoms may include light-headedness and fatigue, a dry mouth, sunken eyes, and more concentrated (and therefore darker) urine.²¹

The body may produce sweat to help balance out the temperature, due to the increase incited by a fever. However, excessive sweating will put more strain on the body’s ability to regulate this. The purpose of sweat in this case is heat loss.² Excessive sweating may make temperature regulation during a febrile illness more difficult.

Due to the increase in fluid loss from the body (particularly water),²² it would be important to monitor hydration when someone is ill with a fever. In fact, it is recommended to drink more fluids when you have a fever, preferably water. This may mean increasing water intake during episodes of excessive sweating.²⁴ It is also recommended to avoid alcohol, as this can contribute to dehydration.²³ Someone may monitor their water levels/fluid intake by checking urine colour and the number of times they urinate in a day (the aim is once every 2–4 hours).²⁴ Losing electrolytes can also contribute to dehydration, and these can be lost through hyperhidrosis. Electrolytes include substances such as sodium and potassium, which can be found in fruits and vegetables (such as bananas and potatoes).²⁴

Hyperhidrosis can be an uncomfortable condition to have to handle. People may find they become unhappy and lack confidence because of excessive sweating.²⁵ There are, however, different ways to manage and treat hyperhidrosis to reduce its dampening effects on one’s quality of life.

Febrile diseases already have their own symptoms, such as hot/flushed skin and chills.²⁶ Hyperhidrosis can worsen the experience by adding symptoms related to issues with the skin. Due to the moist environment induced by excess sweating, skin can pale and come away easily over time (skin maceration). This can leave a person at risk of a skin infection. Sweating can also increase fatigue,²⁹ which may already be a symptom of the fever a person is experiencing.²⁸

Management strategies for hyperhidrosis in febrile illnesses

Medical and lifestyle approaches

Despite being an uncomfortable condition, there are several ways to manage and treat hyperhidrosis. On a preventative level, reducing emotional stress and situations where the person is exposed to too much heat may help prevent excess sweating. To prevent discomfort, especially around other people, it may be worth considering:

• Regular cleansing: Maintaining a regime of regular cleansing, such as daily bathing with soap followed by complete drying of the skin²⁷
• Footwear: Changing and cleaning or freshening shoes frequently²⁷
• Absorbent pads: Wearing absorbent pads for the underarms²⁵
• Spare clothing: Carrying extra clothing²⁷
• Clothing choice: Choosing clothing that is light and not tight-fitting, and black or white1
• Sweat triggers: Keeping track of excessive sweat triggers to avoid in the future²⁷ (this could include alcohol or spicy food¹)
• Sweating location: Noting where the sweating occurs, as it may be focal hyperhidrosis, which is specific to certain areas³⁰

As described earlier, it is also important to stay hydrated, and to ensure adequate intake of foods containing electrolytes. These can be monitored throughout a person’s daily diet and will help prevent further complications.

Given the potential skin issues that can occur as a result of excess moisture, it would be helpful to prevent the build-up of sweat on the skin. We already mentioned absorbent pads and daily bathing, but it may be beneficial to keep the skin dry where possible (not unhealthily so, of course). In the event of skin infection, seek advice from a medical professional.²⁷

Another method of treatment is by targeting the sweat glands themselves. For example, antiperspirants (which can also help with any odour-related issues) can be applied at home, and block the sweat glands. More serious treatment may involve monthly injections with botulinum toxin, surgery, or electrical treatment via iontophoresis.²⁷

It is also a possibility that hyperhidrosis is secondary to another condition. Therefore, treatment of this other condition may also limit excessive sweating.²⁷

Special considerations for people with chronic hyperhidrosis

Many of the above recommendations may prove helpful in long-term management of hyperhidrosis. Chronic excessive sweating may mean longer skin exposure to excess moisture. Resultant infections may be fungal or bacterial; hence, it is very important to avoid skin maceration.³¹

On another level of management, it is important for people to address any negative side effects on one’s mental health and the psychological consequences of the condition (such as depression or anxiety). This may involve participating in support groups and taking individual counselling.²⁷ These interventions may also help someone with repeat cases of febrile illnesses experiencing excessive sweating.

Summary

Febrile illnesses can create uncomfortable living conditions for a person, with the typical symptoms of fever. Sweating is already a symptom, but having an excess sweat build-up can worsen the situation. Managing hyperhidrosis during the course of a febrile illness is important for comfort, health and hygiene. It would be interesting to see further research linking febrile illnesses and hyperhidrosis. The two appear to be correlated, but exactly how, and any underlying conditions, may be worth looking further into.³²