Ulcers are painful sores that are very slow to heal and can reappear. They can happen to anyone. Where they appear is based on what caused them, and they can appear inside as well as outside the body. There are many different types of ulcers.
The main types of ulcers are as follows:

Stomach ulcers
Out of the types of ulcers, stomach ulcer or peptic ulcer is the most common. They cannot be seen and form in the inner linings of the stomach, esophagus, or the upper portion of the small intestine. They form when the digestive juices erode the membrane protecting the stomach or the intestine. There are three main types of ulcers in the stomach – gastric, esophageal, and duodenal ulcers. They are mainly caused by infections caused by the H. pylori bacteria, long term use of medications such as ibuprofen or aspirin, among others. Symptoms include bloating, belching, heartburn, nausea, and vomiting.

Mouth ulcers
One of the main types of ulcers is mouth ulcers or canker sores, small sores or inflammation that forms on the insides of our mouth, the base of the gum, and tongue. These ulcers can be caused by various reasons like hormonal changes, certain food allergies, deficiency of vitamins in the diet, diseases, bacterial infection, or even by brushing your teeth too hard.

Leg ulcers
Leg ulcers are painful and can take a long time to heal. There are different types of leg ulcers, depending on the cause and region of the infection. Most start with an injury that did not heal properly because of some other health problem. The most common type of leg ulcers are the venous ulcers (they typically develop due to damage in the vein caused by irregular blood flow) and arterial ulcers (which occur due to problems in the arteries). Diabetes can also lead to ulcers by causing nerve and blood flow issues. These mainly appear in the legs.

Genital ulcers
Another main type of ulcer is genital ulcers, which form on the penis, vagina, or rectum. They are mainly caused by STDs like syphilis or herpes. Additionally, other causes of this type of ulcer are injuries or an allergic reaction to skincare products. Symptoms of genital ulcers include soreness in the infected region, rashes, bumps, swollen glands in the groin area, itching, and sometimes fever.

Corneal ulcers
Corneal ulcers are the main type of ulcers that occur near the cornea or the surface of the eye. They can cause redness and pain, causing a slight discomfort similar to the feeling of something being stuck in your eye. Typically, the causes of a corneal ulcer include dry-eye syndrome, injury to cornea, or infection. They can cause serious eye problems and can lead to blindness.

As seen above, there are various types of ulcers, and all of them are caused in different parts of the body. Most of the ulcers are easily treated. However, if the condition worsens, it is best advised to consult a doctor immediately.