Itchy armpits are not very common, or at least when the condition does occur, it tends to be rather mild and temporary. As is the case with your wrists and ankles, two parts of your body that are the most susceptible to itching, scratching an itch that is happening under your arms is often done without you even thinking about it. There are some diseases or disorders however that can cause severe or even chronic itching, and these diseases or disorders often require medical attention. Most of them are uncommon however. Fortunately, the more common causes of itchy skin tend to be accompanied by the mildest symptoms and are in most cases easily treated. The anatomy of the armpit, as will be described below, has quite a bit something to do with why you may at times experience itching in that particular area of your body. As far as the itching itself is concerned, it is not a disease. Itching is a manifestation of a disease or a disorder. Itching, or pruritus – the medical term for itching – could simply be looked upon as one of your skin’s ways of complaining.
The Anatomy of the Armpit
Whenever the anatomy of the human body is the subject of study, the armpit is usually not given a great deal of attention. After all, a pit is something that is usually hollow or empty, and the same is true to some extent in the case of one’s armpit. When you extend your arm, there is nothing there except skin and perhaps, if you are a man, some hair.
If you were to take up the study of itchy armpits, or happen to personally experience the problem, understanding a little about the anatomy of that part of your body might at least offer some insight into why you might be experiencing some itching. In most cases, the cause is related to hygiene, but there are a few things about the makeup of the armpit that sometimes come into play.
Your armpit is formed in accordance with the relationship between the arrangement of your shoulder bones and muscles and your chest wall. Your armpit lies directly beneath your shoulder joint. Your armpit is not a mass of muscles; nevertheless, it contains a large number of blood vessels and a large number of lymph nodes. There are also a large number of hair follicles and sweat glands in your armpit.
The anatomy of one’s armpit can contribute to itching in at least three different ways. First, because of the number of lymph nodes in the area, itching can be the result of a lymph node problem. Secondly, when your arm is at your side, your armpit is closed. The area is therefore constantly warm at times and damp as well, making it a breeding ground for bacteria and fungi. There are a large number of blood vessels in your armpit. Many of these blood vessels lie near the surface of your skin and consequently keep your armpit quite warm. Your armpit is in fact the warmest part of your body and is a place where your body temperature can be taken with a good deal of accuracy. Again, the combination of warmth and dampness can lead to skin irritations. A third reason would be the high concentration of sweat glands found in the armpit makes it a part of your body that is especially susceptible to heavy perspiration, as anyone wearing a nice shirt or blouse in an overly warm room can often attest to.
The medical term for itchy skin is pruritus. The three most common causes of underarm pruritus are disease, chemical irritants, and poor hygiene. Pruritus is the Latin word of itch. It is in itself not a disease. It is a manifestation of a number of skin diseases or disorders including eczema and various forms of dermatitis. There are also a number of underlying diseases that can cause what is known as systemic pruritus. These diseases include uremia, hypothyroidism, HIV infection, and Hodgkin’s lymphoma, to name a few. Pruritus that is confined to one’s armpit is most often caused by a disorder affecting the integument in the immediate area. It can be mild to severe with its treatment depending upon the degree of severity as well as the underlying cause. Pruritus originates within the free nerve endings of the skin. The most common areas on your body that are likely to be affected by pruritus are the ankles, wrists, and the armpits, three areas where sweating, friction, or a combination of the two will quite often occur.
Nine Common and Uncommon Diseases, Disorders, or Conditions
A number of the diseases or disorders described below are prefaced with the word ‘axillary.’ Axillary is the anatomical term for the region defining the armpits. A number of the diseases or disorders discussed below could affect any part of your body. Folliculitis would be one example, as any part of your body might become prone to this particular infection. When your armpits are affected, especially if only your armpits are affected, your condition would properly be referred to as axillary folliculitis.
Axillary folliculitis – Axillary folliculitis is a condition in which one or more of the hair follicles in the armpits have become infected. The infection is usually bacterial in nature, with the pathogen most often being Staphylococcus aureus, although other types of bacteria can sometimes be involved as well. In most instances, folliculitis is superficial and clears up on its own rather quickly. The small white pimples that are characteristic of the infection will tend to itch however until the infection has been dealt with, usually by the body’s immune system. In some cases, folliculitis can occur deeper in the dermal layers, affecting the entire hair follicle instead of causing an infection only near the surface. Instances of deep folliculitis can sometimes lead to scarring. If the infection is deep and severe, another condition can sometimes develop, that being a boil or a carbuncle, which is a cluster of boils. Axillary folliculitis is not terribly common as folliculitis is more often encountered in the scalp or in a man’s beard, where it is commonly referred to as barber’s itch. One potential cause of axillary folliculitis is spending time in a hot tub where the chemical levels have not been properly balanced.
Intertrigo – Intertrigo is a very common condition and, in most cases, is simply referred to as a rash. Intertrigo affects those integumentary areas where skin folds are present, and like some other skin disorders, it most often appears in the groin area, the lower abdomen, and in the armpits. Itching and redness are the most common manifestations of intertrigo, but in some cases, the skin may become cracked or crusty or ooze a foul-smelling fluid. One of the more commonly encountered forms of intertrigo is diaper rash. Intertrigo, especially if left untreated or unattended, can sometimes be accompanied by a fungal or bacterial infection. The highest risk factors for contracting intertrigo are obesity, diabetes, exposure to high heat and humidity, and poor hygiene.
Axillary lymphadenopathy – Axillary lymphadenopathy is a condition in which the lymph nodes under the armpits have become enlarged. Axillary is, as has been noted, the anatomical term for the armpit, while adenopathy is the medical term for a glandular disease or the enlargement of glandular tissue, which would include lymph nodes, of which there are more than six hundred in the body. Most cases of axillary lymphadenopathy are caused by relatively benign diseases. The term itself usually applies to lymph nodes that are abnormal in size, in number, or, in general, in consistency. Axillary lymph nodes are generally palpable, meaning they can be felt when applying pressure to the outside of one’s skin, whereas most lymph nodes in the body are not. Most cases of axillary lymphadenopathy show only mild symptoms, which can include itching under the axillae, or may show no symptoms at all. Larger-sized nodes are usually either closely monitored or removed although instances of them becoming malignant are rather uncommon. Less than one percent of the general population appears to have a history of this disorder.
Tinea axillaris – Tinea corporis is the medical term for ringworm. When only one’s armpit is infected, the condition is referred to as tinea axillaris, or, more commonly, armpit fungus. Tinea axillaris is an infection and as such is treatable. The armpit is an ideal place for such an infection to take hold, as it is an area characterized by low light due to clothing, moisture due to sweating, and the fact that the armpit is the surface area of the body having the highest body temperature. Tinea axillaris is not a particularly common condition. Those who most likely to be affected are those with axillary hyperhidrosis, a relatively rare disorder that involves excessive sweating and is discussed below. One of the more common symptoms of ringworm is itching of the skin.
Psoriasis – Psoriasis is an autoimmune condition that causes red plaques to form on one’s skin. The skin will often become flaky and can become itchy as well. There is also a condition known as inverse psoriasis, which often occurs in the armpits. In the case of inverse psoriasis, the red patches still appear but they are smooth and not flaky. The skin can become swollen and itchy. One of the more common causes of inverse psoriasis is obesity as the folds in the skin can cause friction and lead to excessive perspiration.
Hidradenitis suppurativa – Hidradenitis suppurativa, or HS, is a disease affecting the sweat glands, in particular the sebaceous sweat glands found in the groin area, under the breasts, and in the armpits. Another name for this disease is acne inversa. This noncontagious disease is characterized by clusters of cysts, some of which can become quite large, as well as the appearance of abscesses. These abscesses, upon bursting, can be slow to heal or do not heal at all. Itching is one of the symptoms of this disease. Pain or tenderness is another. HS is treatable but is not curable. It is not a common disease and is therefore one that is poorly studied, and its causes remain unknown. One school of thought is that the onset of the disease is often triggered by a blocked gland. Mild cases can sometimes be self-treated while extreme cases may require surgical intervention.
Miliaria rubra – Miliaria rubra is a somewhat common disease that takes on the form of a heat rash. Miliaria tends to affect those who are confined to bed rest or have been exposed to a hot and humid environment for some length of time. Miliaria rubra is sometimes referred to as ‘prickly heat.’ The primary symptoms are itchy armpits and red bumps that form under the armpits. Sweating is usually not a factor; in fact, it is the lack of sweating that is the problem since the condition is often triggered by sweat glands that have become blocked, and while there is still perspiration, it has become trapped under the skin. There are several different types of miliaria, with miliaria rubra being the most common. Other areas of the body besides the armpits can be affected, and if the disease is widespread, there is a danger of heat exhaustion due to an inability to sweat, although the risk of heat exhaustion is a rather small one. Miliaria rubra is a fairly common disease in tropical regions.
Axillary dermatitis – There are several types of dermatitis that can affect the area within the armpit, including contact dermatitis, allergic dermatitis, and atopic dermatitis, the latter case being instances of dermatitis for which the cause cannot be determined. Of these, contact dermatitis is the most frequent and tends to be caused by the skin coming into contact with an irritant. In some cases however, soap or a deodorant may contain an allergen and it is the allergen rather than a chemical reaction that causes a problem. Both allergic reaction triggers and irritants that can damage one’s skin can cause a rash, and it can sometimes be difficult to tell the two types of rashes apart. Usually, if the rash appears suddenly, it is due to contact dermatitis. In cases of allergic dermatitis, it may take a day or more for a rash to appear. Allergic dermatitis tends to cause itching under the armpits, while contact dermatitis is often more painful than it is itchy.
Axillary hyperhidrosis – Hyperhidrosis is a disorder of the sweat glands, a disorder that causes excessive sweating. The three areas of the body that are most apt to be affected with hyperhidrosis are the palms of the hands, the soles of the feet, and under the armpits. When the armpits are affected, the disorder is called axillary hyperhidrosis. The causes of this condition are not well understood, and while there are certain things that can trigger an episode of excess sweating, the sweating often occurs spontaneously and seemingly without any provocation. Hyperhidrosis is believed to be influenced by the sympathetic nervous system, which is the system that prepares the body to deal with stressful situations. The sympathetic nervous system usually promotes the body’s ‘fight or flight’ responses and does not cause excessive sweating, but with people who have hyperhidrosis, it does. Hyperhidrosis is treatable by both surgical and nonsurgical methods. The disorder in itself does not usually cause itching, but itching may occur if the excessive moisture that is produced causes peeling, which can affect the integrity of the skin and in turn lead to infections that cause one’s skin to become irritated and itchy. Axillary hyperhidrosis is believed to affect less than one percent of the population.
Treating Itchy Armpits
Treatment can vary depending on the cause or the nature of the disorder. In many cases, it is only the symptoms that require treatment. In other instances, the underlying cause of the disorder may need to be addressed. In cases of a simple rash, the application of a medicated cream such as a mild corticosteroid may be sufficient to relieve the itching and prevent any further progression of the disease or disorder. Taking an oral medication may be recommended in some instances, while other causes of itching in the armpit area may occasionally call for surgical intervention. Since a number of the disorders discussed here are triggered by warmth, moisture, or friction, wearing loose clothing that allows for proper ventilation, keeping the underarms as dry as possible, and practicing good hygiene will more often than not allow skin conditions to heal and prevent those conditions from reoccurring, or prevent the conditions from occurring in the first place. Severe or chronic conditions should of course always be referred to a physician. The majority of the conditions that have been discussed here are relatively harmless but can sometimes be a cause for embarrassment.