The short answer is yes and no. Like many diseases, psoriasis is influenced by both genetics and the environment.
The exact role these factors play is still a developing story, however we already have quite a bit of insight into how each can affect the course of psoriasis. Our genes are inherited from our parents, and certain genes may predispose us to develop psoriasis at some point in our lives.For example, if a parent has psoriasis and one child develops the condition before age 15, siblings have a 50% chance of developing psoriasis, too. Identical twins have a 67% risk of sharing the disease. Certain HLA types can increase the risk of developing psoriasis by up to 6 times. Race can also be a predisposing genetic factor; those with fair-skin have a higher likelihood of developing the disease than darker-skinned individuals. While you cannot change your genes, you can alter your environment and make choices that influence your risk of a psoriasis breakout.
Managing related conditions may help you also fend off psoriasis. Stress, anxiety, depression and related emotional disorders can trigger psoriasis. In addition, psoriasis has been known to appear after an upper-respiratory tract infection, such strep throat or sinusitis. Psoriasis tends to be particularly severe in those with HIV/AIDS. Treating conditions such as these may also help keep psoriasis in check.Medications
Certain medications can trigger or worsen psoriasis. These include:
- beta blockers and ACE inhibitors, used to treat high blood pressure
- the mood disorder drug lithium
- antimalarials related to hydroxychloroquine (which, today, are more likely to be prescribed for arthritis or lupus)
If it's an option for you, switching drugs or reducing your dose may help reduce risk of a psoriasis breakout.
Of particular importance are those risk factors for which you have the most control over: physical environment, obesity, diet, alcohol consumption, and cigarette smoking.
Cold, dry air tends to worsen psoriasis, while a warm and humid climate is typically helpful, especially when natural sunlight can reach the skin. Although many reports have positioned obesity as a risk factor for psoriasis, one study demonstrated that obesity appears to be a result of psoriasis. A fruit and vegetable-rich "healthy" diet may be somewhat protective. Alcohol consumption increases the risk of developing and the severity of psoriasis to a small degree. Cigarette smoking worsens psoriasis with a demonstrable dose-response relationship implying a causal effect. Nevertheless, it is not entirely clear if alcohol and smoking are increased due to the stress of psoriasis or being a significant cause of the disease.
What You Can Do
You can't choose your parents (or your genes), but you can take measures to minimize the risks of psoriasis if you are genetically predisposed it. Remember to:
- Treat conditions associated the psoriasis breakouts early and thoroughly.
- Avoid medications known to flare psoriasis whenever possible.
- Maintain a normal body weight.
- Eat a diet rich in fresh fruits and vegetables.
- Eliminate or minimize smoking and alcohol.
- Keep skin moist with a humidifier and moisturizer.
- Plan moderate exposure to natural sunlight, without burning (take a walk outside on your lunch break, for example).
Camisa C. Handbook of Psoriasis, 2nd Ed. Blackwell Publishing, USA 2004
Medical nutrition therapy as a potential complementary treatment for psoriasis--five case reports