The term “subcutaneous nodule” is a medical phrase that can cover basically any sort of lump or bump that occurs beneath the skin. These bumps are noticeable and can be felt on the surface, but they aren’t skin blemishes in and of themselves the way warts and most moles are. Many different things cause them to form, and while most are benign, some are signs of much more serious conditions. Medical experts typically advise people to keep an eye on any nodules they notice, and get an evaluation if any seem to move, change in size, or multiply.
How They Form
It is somewhat difficult to nail down exactly how or why nodules form since they come in so many different varieties. They can appear anywhere on the body and in a wide range of sizes. They can be so small as to be barely felt, or large enough to be easily visible; they may be filled with liquid or with a solid mass of cells or other tissue. Some nodules, such as abscesses, can spontaneously erupt and drain fluid, while others are nothing more that fat that is encapsulated under the skin. Some conditions, such as metastatic cancer, also cause nodules to appear, though in this case the bumps are just one of many other, more serious symptoms.
In all cases, though, the bumps form under the body’s innermost layer of skin, known as the subcutaneous tissue. The skin has three main layers: the outer layer, or “epidermis,” which actually has five layers of its own; the middle layer, or “dermis,” which has two layers of its own; and the inner, subcutaneous level. Depending on what they’re made of they may be tender to the touch, and often look red at first, and they can appear almost anywhere on the body depending on what is causing them to grow.
Benign or Harmless Nodules
Bumps under the skin aren’t usually considered normal, but they aren’t always harmful, either. Some insect bites can result in subcutaneous nodules, particularly if the bitten person has an allergic reaction to the toxins or other insect fluids. Most bites present as surface bumps that go away within a few days, but when the skin cells react badly, fluid or irritation can also build up below the surface. Most of these will disappear on their own after a week or so, but should be watched to be sure they don’t get infected or grow larger.
Some people are also genetically predisposed to benign subcutaneous nodules. These are usually considered harmless cosmetic flaws, and most are made up of fat cells or other cellular matter. These may not ever go away but rarely pose problems. People who are concerned about them for aesthetic purposes can sometimes get them surgically removed, but in some cases the removal can leave a more obvious mark than the nodule ever did.
Cysts, which are generally harmless pockets of fluid, may also cause nodules. Ganglion cysts are some of the most common, and generally occur on the top of the hand, foot, or on the wrist. Rheumatoid nodules may develop in people with rheumatoid arthritis, typically on or around the joints that are inflamed.
More Serious Causes
Nodules can also be a sign that something is more seriously wrong with a person’s health, however, which is why many medical professionals recommend that people pay close attention to any lumps and bumps that they see. Granulomas, for example, are a type of subcutaneous nodule caused by inflammatory disorders that can have a serious impact on the functioning of a person’s internal organs. When tissues are irritated or inflamed, toxins and excess bacteria often release into the blood, which can clump up to form nodules beneath the skin.
Metabolic disorders such as hemochromatosis can also result in nodule formation, and are a sign that a person isn’t properly allocating energy or blood sugars. In rarer cases, the nodules can also be a symptom of metastatic cancer. When cancer is the cause, the bumps are often actually small tumors that, if left untreated, can spread cancerous tissue to the skin, blood, and nearby organs.
Problems with Self-Diagnosis and Care
People who notice subcutaneous nodules are often tempted to treat them themselves, though most medical experts discourage this. Topical creams designed for ordinary insect bites and rashes aren’t usually able to penetrate down to the skin’s lower-most level, and in some cases can cause more harm than good.
Puncturing the nodule to drain it or relieve pressure can be dangerous, too, since it’s often really difficult to tell what it’s made of. Draining a nodule filled with bacteria, for instance, could actually cause an infection to spread or make the underlying condition worse. People who aren’t sure what to do are usually advised to take a “wait and see” approach to see if things will go away on their own, and to carefully document their symptoms and reactions in the meantime.
When to Seek Help
Skin bumps that are painful, swollen or tender to the touch, or that seem to be growing in size or number should typically be evaluated by a skin specialist. Experts can often diagnose more serious conditions early on, and can stop many other problems before they start. Even though most skin nodules aren’t anything to be worried about, getting them checked out is a good way to rule out possible issues.