Understanding Infected Sweat Glands

Think about your armpit, or the inner part of your upper thigh. Sensitive spots, aren't they? The nerves that give our skin its remarkable sensitivity are packed tight in those zones, making even a small injury there feel much worse than it actually is.

Now, with that image fresh in your mind, consider this:

Infected sweat glands.

Makes you cringe, doesn't it?

The idea of a swollen mass growing in some of the body's most sensitive areas is an uncomfortable thought, but for people suffering from infected sweat glands, it can be a painful fact of life. Sweat gland infections on visible parts of the body can be embarrassing, and severe infections can hamper a person's ability to move comfortably.

While there are a number of different causes for infected sweat glands, the symptoms are often similar: A spot under the skin swells and becomes painful. It may form a boil that ruptures and oozes pus, or may develop into a rash of tiny vesicles, blister-like bumps that itch and ooze fluid when scratched. Over time, a minor infection may subside, leaving little more than a lump of scar tissue. More severe infections, however, can leave large scars, which may require surgery to remove. And while some sweat gland infections appear to be made worse by excess body weight or time spent in a hot climate, sweat gland infections are fairly widespread. No single gender, age group or ethnic group has a genetic free pass from this uncomfortable type of infection [sources: Baker, Hijazy].

So what causes a sweat gland infection? How does a person treat or, better yet, avoid this painful condition? To answer these questions, it helps to understand what sweat glands are, what they do and how their very design makes them susceptible to infection.

What Are Sweat Glands?

Sweat is an essential part of normal bodily function. This liquid made up of water, sodium and a mix of minerals acts as the body's radiator fluid. When your internal temperature rises, glands in your skin release sweat onto its surface, where it evaporates, cooling the skin and lowering your body temperature [source: Porter].

Human sweat glands come in two forms: eccrine sweat glands, which cover most of our skin, and apocrine sweat glands, which are concentrated in the scalp, armpits and groin. The two glands produce different types of sweat. Eccrine glands produce the sweat that cools your body when its core temperature rises, while apocrine glands release a thicker, fattier substance in response to stress, such as a tense argument or an intense sporting event. Scientists suspect apocrine sweat contains pheromones, hormonally driven indicators of mood or fertility. But most people recognize apocrine sweat as the source of body odor; naturally occurring bacteria on the skin consume the substance, and their waste is what causes the unpleasant smell after an intense workout [sources: Baker, Mayo].

Both types of sweat gland share some structural features. The base of a sweat gland is a coiled structure nestled in the border between the skin's thick middle layer, or dermis, and the subcutaneous layer of fat at the base of the skin. A series of ducts leading up from the coiled structure channel the gland's secretions to the skin's surface.

The difference between eccrine and apocrine glands, beyond the type of sweat they produce, comes in their location. While eccrine glands open directly onto the skin's epidermis, or outer surface, apocrine glands release their sweat at the root of hair follicles. Consequently, infections of the apocrine glands are often referred to as folliculitis [source: Baker].

The structure and function of sweat glands plays a key role in many types of sweat gland infections. Read on to learn how sweat glands can become victims of their own design.

What Causes a Sweat Gland Infection?

For all their vital function, sweat glands have an inherent weakness: Their tiny ducts can be prone to clogging. If this happens, the sweat that would normally exit the body gets trapped in the gland, giving infection-causing bacteria a safe haven to grow and multiply. While infections in both eccrine and apocrine sweat glands involve clogged ducts, the root causes of infection vary by gland type.

Miliaria, an infection of the eccrine sweat glands, can be triggered by excessive sweating or too much time spent in a hot, humid environment. Sweat may build up in blocked eccrine glands to form miliaria crystalline, a rash of tiny, painless vesicles. If infection ruptures the gland's ducts, sweat can move into the skin around the glands, causing an itchy inflammation called miliaria rubra, or "prickly heat." If this condition advances, the infected glands can swell with pus in a condition known as miliaria pustulosa. And in miliaria profunda, the infection's most advanced form, sweat leaks into the surrounding dermis, causing a severe burning sensation [sources: Baker, New Zealand, O'Connor].

Because they affect hair follicles, infections of the apocrine glands are often referred to as folliculitis. Unlike miliaria, these infections can occur regardless of the amount that someone sweats. The exact disease triggers aren't always known, but people with certain complicating conditions can be more prone to folliculitis [sources: Bakr]. Most types of folliculitis involve keratin or other bodily substances plugging the apocrine gland's duct where it opens to the hair follicle, leading to infection in the gland. While some types of folliculitis may be due to genetic predisposition -- the body fails to shed skin and hair cells properly, leading to plugged ducts -- other types of the infection can be brought on by poor hygiene, such as shaving the armpits or groin with a dull, dirty razor, or chafing from tight-fitting clothing [source: Jovanovic].

One of the most advanced and uncomfortable forms of apocrine gland infection is hidradenitis suppurativa, also known as acne inversa. The condition appears as blackheads and painful, sometimes pustulent bumps in the groin and armpits. It can persist for years, and often gets worse as the victim ages. Chronic bouts of hidradenitis suppurativa can form networks of scars just below the skin's surface [source: Jovanovic].

Why do humans sweat?

Sweat was a vital tool for our ancestors. Many mammals control body heat by panting, but this only transfers heat from their mouths. Sweating, on the other hand, transfers heat from the entire skin surface; it gives humans a much bigger radiator than other mammals. Researchers hypothesize that this allowed primitive hunters to cover long distances in pursuit of game, while the panting animals they pursued overheated and collapsed from exhaustion [sources: Liebenberg, Porter].

Treating Infected Sweat Glands

Because of the different types of glands involved in various sweat gland infections, treatments can range from simple to severe. For miliaria, good hygiene can often prevent the buildup of gland-blocking sweat and bacteria on the skin. If miliaria erupts, however, it often quickly responds to a change in temperature: Getting out of the heat and into a cool, dry area can reduce the severity of symptoms and give the skin a chance to heal [source: Baker].

Apocrine sweat gland infections may require a more hands-on approach to treatment. Treatments such as warm compresses may help open the clogged ducts, but it may take antibiotics to knock out the bacteria behind the pustular inflammation common to apocrine sweat gland infections [source: Zacherle]. The scarring that forms in severe, chronic infections such as hidradenitis suppurativa may require a more drastic step. If the scars are unsightly or cause discomfort, the doctor may remove the section of skin containing them. This procedure is often reserved for only the most severe cases, where the long-term process of letting a section of skin regenerate on its own is a small price to pay for relief from painful, persistent infection [source: Jovanovic].

Preventing Sweat Gland Infections

One of the easiest ways to prevent your sweat glands from becoming infected is to keep your skin clean. This removes the excess bacteria and sweat that causes miliaria. Likewise, it helps to observe proper hygiene when shaving body parts with high concentrations of apocrine sweat glands, such as armpits or the groin area. Shave with the grain of the hair, not against it, and wash the area immediately after shaving. Keeping your razor clean and sharp also helps reduce the tiny that can lead to infection [source: AOCD].

Other simple steps can help prevent miliaria: If you're going to spend time in hot, humid environments, make sure your skin can breathe by wearing loose, breathable clothing. And try to intersperse time in the heat with time in a cool place, giving your body temperature a chance to drop and your sweat glands a break from cooling your skin [sources: Baker, O'Connor].

If you have a history of apocrine sweat gland infections, you can reduce the chance of a flare-up by avoiding tight-fitting clothing; chafing can lead to new infections. And some research suggests that losing weight, while not a cure for chronic infections, appears to help reduce the frequency of infections like hidradenitis suppurativa [source: Kineston].

Sweat gland infections are no fun. Between the itching, pain and potentially embarrassing rash, they can be a major health problem for the people they affect. But arming yourself with knowledge about what causes them, and how to prevent them, can reduce the amount of time you spend dealing with these uncomfortable skin conditions.