The cause of psoriasis isn’t fully known, but it's thought to be related to the immune system and its interaction with the environment in people who have the genetic susceptibility. More specifically, one key cell is a type of white blood cell called a T lymphocyte or T cell. Normally, T cells travel throughout the body to detect and fight off foreign substances, such as viruses or bacteria. If you have psoriasis, however, the T cells attack healthy skin cells by mistake, as if to heal a wound or to fight an infection.
Overactive T cells trigger other immune responses. The effects include dilation of blood vessels in the skin around the plaques and an increase in other white blood cells that can enter the outer layer of skin. These changes result in an increased production of both healthy skin cells and more T cells and other white blood cells. This causes an ongoing cycle in which new skin cells move to the outermost layer of skin too quickly — in days rather than weeks. Dead skin and white blood cells can't slough off quickly enough and build up in thick, scaly patches on the skin's surface. This usually doesn't stop unless treatment interrupts the cycle.
Just what causes T cells to malfunction in people with psoriasis isn't entirely clear, although researchers think genetic and environmental factors both play a role.
Psoriasis typically starts or worsens because of a trigger that you may be able to identify and avoid. Factors that may trigger psoriasis include:
- Infections, such as strep throat or thrush
- Injury to the skin, such as a cut or scrape, bug bite, or a severe sunburn
- Cold weather
- Heavy alcohol consumption
- Certain medications — including lithium, which is prescribed for bipolar disorder; high blood pressure medications such as beta blockers; antimalarial drugs; and iodides.
Studies have shown stress can worsen psoriasis. When you're stressed, your body reacts. And while stress is known to make psoriasis worse, psoriasis can make you more stressed out.
Breathe deep and count to 10. Take a relaxing soak in the tub. Call up a friend to vent. Meditate. Focus on the positive and incorporate relaxation techniques into your daily routine. All are ways to bust stress and perhaps help keep psoriasis flares at bay.
AllergiesAre psoriasis and allergies linked? The immune system appears to play a key role in both.
Researchers have found that people with psoriasis are more likely to have a greater number of inflammatory mast cells (see left) -- the kind that trigger allergic reactions, such as swelling and itching -- than people without it. Although psoriasis may be a reaction of the immune system, it is not proven to be an allergic reaction. Studies have found no link between allergens and psoriasis.
AlcoholMany lifestyle choices can affect psoriasis. Drinking alcohol has been associated with psoriasis and its severity. While more research is needed, it's believed that heavy drinking can trigger flares in some people. Doctors say avoid alcohol altogether to help prevent psoriasis flare-ups.
Another reason to put down your drink? Some psoriasis medications and drinking don't mix.
Instead, try a nonalcoholic thirst-quencher like iced tea. Or walk around the block to unwind. Getting exercise and up to 20 minutes of sunlight a day can soothe psoriasis.
Cold or Dry WeatherWinter can be especially hard on those who live with psoriasis. Cold, dry weather can worsen psoriasis, while warm, sunny climates may help alleviate it.
Keep your skin well moisturized. Use thick, creamy lotions after showers and baths and throughout the day. Look for lotions and soaps that are fragrance-free and designed for sensitive skin to help reduce irritation.
You can also use a humidifier in your home during dry months to help keep your skin moist. Keeping the skin moist can help reduce itching and tenderness.
TattoosTattoos can look cool, but to psoriatic skin the tattooing process can be a nightmare. Repeatedly piercing the skin and injecting it with dyes is a major trauma. Trauma to the skin can cause new lesions to appear, often 10 to 14 days later.
Tattoos can also lead to infection -- another psoriasis trigger.
Treat your skin with care. Avoid tattoos and acupuncture, and talk with your doctor about shots.
MedicationsSome drugs used to treat high blood pressure, heart disease, arthritis, and psychiatric disorders can trigger psoriasis.
ACE inhibitors, beta-blockers, and lithium are common offenders that can cause psoriasis flare-ups as well as malaria drugs, such as Plaquenil and hydroxychloroquine, and NSAIDs. Oral steroids such as prednisone work to control flares but may cause a worsening of the condition after coming off long-term use.
Talk to your doctor if your medication is worsening your psoriasis.
InfectionsCommon infections are doubly difficult for people with psoriasis. Yeast infections, thrush, strep throat, respiratory infections, and staph infections are all known psoriasis triggers.
The good news? Once you treat the infection, your psoriasis flare may also calm down.
Cuts and BruisesSlice your hand in the kitchen or scrape a knee and -- pow! -- new lesions may appear where you were injured. This is called Koebner's phenomenon.
Avoid skin injury and trauma when you can.
Wear gloves while working in the garden. Prevent bug bites and sunburn. And use care when trimming nails and shaving.
SmokingResearch shows smoking is directly linked to the severity of your psoriasis. The more you smoke, the worse your flare-ups, with outbreaks most often appearing on the hands and feet.
Kicking the habit may reduce the number of psoriasis flares and, for some, end them.
You don't have to take on the challenge alone. Ask your doctor about ways to smooth the transition to becoming smoke-free.
HormonesPsoriasis can start at any age in both men and women. But it seems to peak in people between the ages of 20 and 30 as well as those between the ages of 50 and 60. Both puberty and menopause also seem to trigger psoriasis patches. Hormones are often thought to be the link.
Interestingly, one study found that high levels of estrogen during pregnancy seemed to improve psoriasis in some women.