Introduction
A bump in humans colloquially refers to a visible or palpable bulge of the skin on a part of the body. The most common causes are water retention, tissue proliferation or organ enlargement. A bulge caused by an injury usually disappears by itself after a few days. A lump that develops without a recognisable cause and becomes bigger and bigger should be examined by a doctor at an early stage. In some cases, this can be a sign of a disease that should be treated.
Causes
The development of bumps is not based on a uniform disease, but there are a variety of possible causes that can lead to the visible or palpable bulge under the skin. A common cause of bumps is blunt trauma, for example, if you hit your head or shin. This can also cause small blood vessels in the skin to burst and blood to leak into the tissue.
Such bumps caused by an injury are most common and in most cases harmless. Depending on their size and location, they usually disappear within a few days. Likewise, insect bites can lead to a bump, which also disappears after a few days.
Another possible cause of bumps is swollen lymph nodes, for example in the neck. In the case of a cold with a sore throat, it is more common for the lymph nodes to enlarge as a sign of the body’s defence against infection. After the disease has been cured, the bumps on the neck usually disappear again.
Another group of bumps are those that occur without any apparent cause. These can occur all over the body and should be examined by a doctor to be on the safe side if they do not disappear or continue to grow after about two weeks. Again, there are a variety of possible causes and only in rare cases is there a disease that needs treatment.
As this type of bumps can be a sign of cancer in a small number of cases, a timely examination is important, as this allows any necessary treatment to be carried out as early as possible. The same applies to rare diseases that lead to the appearance of bumps in different parts of the body. These include, for example, infectious diseases caused by viruses or bacteria.
By localization
A bump that can be felt or seen under the skin is caused by the tissue underneath. A common cause of a bump under the skin is a benign fatty tissue ulcer (lipoma) that can develop all over the body. A lump under the skin in the neck area is often an enlarged lymph node.
Other possible locations for lymph node swelling, which can be responsible for a bulge under the skin, are the armpit region and the groin. Such bumps should be examined by a physician if they have existed for more than two weeks, if they are getting bigger and bigger or if they occur in different parts of the body. In some cases a disease requiring treatment is the cause of the bumps.
A completely different cause of bumps under the skin can be fractures of the abdominal wall. These are bulges of the peritoneum caused by weak points in the abdominal wall. This can lead to a bulge in the groin or at the navel, for example.
Even in the case of such bulges under the skin, a prompt examination by a doctor is recommended. Often, the hernia must be surgically repaired soon, otherwise a life-threatening entrapment of an intestinal loop can occur, resulting in intestinal obstruction. Nevertheless, bulges under the skin are harmless in most cases, disappear by themselves or at least do not need to be treated.
A bump on the head is usually caused by a blunt injury, for example if you bump your head or receive a blow. There the tissue layer consisting of skin, subcutaneous fatty tissue and a tendon plate up to the bony skull is very thin compared to most other body regions. When you hit your head, there is therefore less soft tissue that could cushion the impact of the force.
On the other hand, the tissue water or blood on the head that leaks out as a result of the injury has little room to spread. Therefore, bumps on the head are more likely to occur than if you bump into other parts of the body. In rare cases, a bump on the head occurs without injury or other apparent cause.
If it occurs at the back of the head, it may be a swelling of the lymph nodes as an indication of an inflammatory reaction. A bump on the back of the head, which develops without a trigger, remains for several weeks or becomes bigger and bigger, should be examined by a doctor. In many people, a bony protrusion can be palpated in addition to the one in the middle of the back of the head, which may be mistaken for a bump.
This is completely normal and can be felt well in some people and less so in others. A bump behind the ear is often a swollen lymph node. These components of the body’s own defence system can become enlarged during an inflammatory reaction.
A swelling of the lymph nodes behind the ear can be caused by an inflamed tooth or an inflammation of the middle ear, for example. In addition, various viral infectious diseases cause swelling behind the ear and often also in other areas of the body. A typical bump behind the ear is often caused by the childhood disease rubella.
Children and adults who have no vaccination protection must therefore also be considered for this disease. In this case, a rash develops on the body as well. The cause of a bump on the elbow is often an inflammation of the bursa (bursitis).
The elbow joint, like some other large joints, has bursae that serve as a kind of cushion. An injury or excessive strain (for example during sports) can cause it to become inflamed. The resulting bump is usually very painful, reddened and overheated.
The bursitis is initially treated by immobilising and sparing the joint, occasionally cooling it and, if necessary, taking anti-inflammatory painkillers or ointments. Often, the bruise on the elbow will disappear after a few days as a result of these measures. The most common cause of a bump on the wrist is a so-called ganglion, which is also called an overbone.
It is a bulging elastic blister that can be caused by thickened joint fluid. The bump is benign and does not necessarily have to be removed. In some cases, however, the ganglion can press on a nerve.
This is usually manifested by a tingling sensation or numbness in the fingers of the affected hand. In such cases, the ganglion should be removed by a minor surgical procedure. The same applies if the bump restricts the mobility of the joint or the bump is felt to be disturbing for other reasons.
In some cases, however, the ganglion disappears on its own without treatment, so it is often possible to wait and see. The possible causes of a bump on the back do not differ in principle from those for bumps in general. Often it is the result of a blunt injury such as a fall on the back.
An insect bite can also be responsible for the then usually itchy bump. In addition, sebaceous glands on the back can become inflamed, which can lead to an often painful and reddened lump with purulent contents. Another, likewise harmless cause of a lump on the back is a lipoma.
This is a benign tumour of fatty tissue that usually does not require treatment. A bump on the knee is most often the result of an injury, for example a fall or during sports. An inflammatory process can also be the cause.
Structures that can often become inflamed are bursae, which serve to relieve pressure in the joint. A bump in the hollow of the knee is in most cases a so-called Baker cyst. This is a fluid-filled sac of the connective tissue joint capsule, which surrounds the knee from the inside like a kind of stocking.
Bumps on the shinbone are very common. One reason for this is that the bone lies very close under the skin and there is little cushioning soft tissue to protect against injury. On the other hand, the shinbone can be easily bumped, for example during sports but also on other occasions.
Due to the rather thin layer of tissue that lies on the shin in front of the bone, escaping tissue water cannot be distributed well as a result of an injury. This is why bumps and bruises occur more frequently on the shin bone than on most other parts of the body. A bruise on the shin bone, which develops without a recognisable cause and remains for more than two weeks, should be examined by a doctor.
A bump on the foot can have various causes. Firstly, it can be a so-called overbone, which sometimes occurs on joints and tendon sheaths and is harmless. In addition, the bump can originate from the bony structures of the foot.
In the vast majority of cases, this too is a benign growth that does not require treatment. In some cases, a bump on the foot causes discomfort because, for example, it presses on a nerve or causes pain when wearing shoes. In such cases, the lump should be examined by a doctor and treated if necessary.
