All Diseases

Perimenopause means "around menopause" and refers to the time period during which a woman's body makes its natural transition toward permanent infertility (menopause). Perimenopause is also called the menopausal transition.

Women start perimenopause at different ages. You may notice signs of progression toward menopause, such as menstrual irregularity, sometime in your 40s. But some women notice changes as early as their mid-30s.

The level of your estrogen — the main female hormone — rises and falls unevenly during perimenopause. Your menstrual cycles may lengthen or shorten, and you may begin having menstrual cycles in which your ovaries don't release an egg (ovulate). You may also experience menopause-like symptoms, such as hot flashes, sleep problems and vaginal dryness. Treatments are available to help ease these symptoms.

Once you've gone through 12 consecutive months without a menstrual period, you've officially reached menopause, and the perimenopause period is over.

Periodontitis (per-e-o-don-TIE-tis) is a serious gum infection that damages the soft tissue and destroys the bone that supports your teeth. Periodontitis can cause tooth loss or worse, an increased risk of heart attack or stroke and other serious health problems.

Periodontitis is common but largely preventable. Periodontitis is usually the result of poor oral hygiene. Brushing at least twice a day, flossing daily and getting regular dental checkups can greatly reduce your chance of developing periodontitis.

Peripheral artery disease (also called peripheral arterial disease) is a common circulatory problem in which narrowed arteries reduce blood flow to your limbs.

When you develop peripheral artery disease (PAD), your extremities — usually your legs — don't receive enough blood flow to keep up with demand. This causes symptoms, most notably leg pain when walking (intermittent claudication).

Peripheral artery disease is also likely to be a sign of a more widespread accumulation of fatty deposits in your arteries (atherosclerosis). This condition may be reducing blood flow to your heart and brain, as well as your legs.

Often, you can successfully treat peripheral artery disease by quitting tobacco, exercising and eating a healthy diet.

Peripheral neuropathy, a result of damage to your peripheral nerves, often causes weakness, numbness and pain, usually in your hands and feet. It can also affect other areas of your body.

Your peripheral nervous system sends information from your brain and spinal cord (central nervous system) to the rest of your body. Peripheral neuropathy can result from traumatic injuries, infections, metabolic problems, inherited causes and exposure to toxins. One of the most common causes is diabetes mellitus.

People with peripheral neuropathy generally describe the pain as stabbing or burning. Often, there's tingling. In many cases, symptoms improve, especially if caused by a treatable underlying condition. Medications can reduce the pain of peripheral neuropathy.

Peritonitis is a bacterial or fungal infection of the peritoneum, a silk-like membrane that lines your inner abdominal wall and covers the organs within your abdomen. Peritonitis can result from any rupture (perforation) in your abdomen, or as a complication of other medical conditions.

Peritonitis requires prompt medical attention to fight the infection and, if necessary, to treat any underlying medical conditions. Treatment of peritonitis usually involves antibiotics and, in some cases, surgery. Left untreated, peritonitis can lead to severe, potentially life-threatening infection throughout your body.

If you're receiving peritoneal dialysis, you can help prevent peritonitis by following good hygiene before, during and after dialysis.

A personality disorder is a type of mental disorder in which you have a rigid and unhealthy pattern of thinking, functioning and behaving. A person with a personality disorder has trouble perceiving and relating to situations and to people. This causes significant problems and limitations in relationships, social encounters, work and school.

In some cases, you may not realize that you have a personality disorder because your way of thinking and behaving seems natural to you. And you may blame others for the challenges you face.

Personality disorders usually begin in the teenage years or early adulthood. There are many types of personality disorders. Some types may become less obvious throughout middle age.

Pet allergy is an allergic reaction to proteins found in an animal's skin cells, saliva or urine. Signs of pet allergy include those common to hay fever, such as sneezing and runny nose. Some people may also experience signs of asthma, such as wheezing and difficulty breathing.

Most often, pet allergy is triggered by exposure to the dead flakes of skin (dander) a pet sheds. Any animal with fur can be a source of pet allergy, but pet allergies are most commonly associated with cats, dogs, rodents and horses.

If you have a pet allergy, the best strategy is to avoid or reduce exposure to the animal as much as possible. Medications or other treatments may be necessary to relieve symptoms and manage asthma.

Peyronie's (pay-roe-NEEZ) disease is the development of fibrous scar tissue inside the penis that causes curved, painful erections.

Men's penises vary in shape and size. Having a curved erection is common and isn't necessarily a cause for concern. However, in some men, Peyronie's disease causes a significant bend or pain.

This can prevent a man from having sex or might make it difficult to get or maintain an erection (erectile dysfunction). For many men, Peyronie's disease also causes stress and anxiety.

In a small percentage of men, Peyronie's disease goes away on its own. But in most cases, it will remain stable or worsen. Treatment might be needed if the curvature is severe enough that it prevents successful sexual intercourse.

Phantom pain is pain that feels like it's coming from a body part that's no longer there. Doctors once believed this post-amputation phenomenon was a psychological problem, but experts now recognize that these real sensations originate in the spinal cord and brain.

Although phantom pain occurs most often in people who've had an arm or leg removed, the disorder may also occur after surgeries to remove other body parts, such as the breast, penis, eye or tongue.

For some people, phantom pain gets better over time without treatment. For others, managing phantom pain can be challenging. You and your doctor can work together to treat phantom pain effectively with medication or other therapies.

Phenylketonuria (fen-ul-ke-toe-NU-re-uh), also called PKU, is a rare inherited disorder that causes an amino acid called phenylalanine to build up in your body. PKU is caused by a defect in the gene that helps create the enzyme needed to break down phenylalanine.

Without the enzyme necessary to process phenylalanine, a dangerous buildup can develop when a person with PKU eats foods that are high in protein. This can eventually lead to serious health problems.

For the rest of their lives, people with PKU — babies, children and adults — need to follow a diet that limits phenylalanine, which is found mostly in foods that contain protein.

Babies in the United States and many other countries are screened for PKU soon after birth. Recognizing PKU right away can help prevent major health problems.