What Is Psoriasis?

Psoriasis has been recognized for centuries, possibly as early as 900 B.C. However, the first medically accurate description of this condition was made in 1808 by an English dermatologist named Robert Wilan. Today, Mosby's Medical Dictionary gives us the modern definition: "a common, chronic skin disorder characterized by circumscribed red patches covered by thick, dry, silvery, adherent scales that are the result of excessive development of epithelial (skin) cells."

Put simply, psoriasis is caused by too many skin cells developing at once. This results in patches of reddened skin with silvery scales on the surface.

The most common places for psoriasis to appear first are the knees, elbows, lower back, and scalp. Sometimes, however, it may initially appear, or evolve from a previous form, as:

• one or a few solitary patches that come and go

• widespread guttate (drop-like) lesions that seem to suddenly appear

• erythrodermic psoriasis, a general redness all over the body, often with scaling

• pustules — pus-filled lesions — on the palms of the hands and soles of the feet

• lakes of pus, with definite physical symptoms (This form is sometimes fatal.)

• psoriasis-linked arthritis, commonly of the lower back or of the hand and foot joints

• the Koebner phenomenon, in which lesions appear in places where the skin has been injured

Whatever form psoriasis takes, usually the skin erupts symmetrically — that is, lesions appear in similar places on each side of the body. When symptoms do appear, some people experience severe itching, while others have none at all.

Who Gets Psoriasis?

It is estimated that 2 percent of the world population has psoriasis, although this disease is relatively uncommon in parts of Asia and Africa. In the United States, psoriasis affects approximately 2.5 to 7 million people. Of these, more than 1 million have moderate to severe forms of psoriasis.

The condition affects people of all ages, from newborns to the elderly. Usually it starts in early and middle adulthood, although 10 to 15 percent of cases start before age ten. Males and females suffer from psoriasis equally.

How Is a Diagnosis Made?

Unless the psoriasis takes an unusual form, most dermatologists can make a diagnosis easily. When it is difficult to tell at first glance, several clues may indicate its presence. These include:

• family history of psoriasis

• fingernails/toenails that are pitted, or appear lifted off the nail beds

• a pinkish rash in the crease or cleft of the buttocks

• skin patches with sharp margins

When psoriasis is suspected but not confirmed, a skin biopsy may also prove useful.

How Does the Disease Progress?

Psoriasis pursues an unpredictable course. It may be limited to a few lesions that seem to come and go with stress, or it may be more widespread. Some individuals have only scalp involvement. The most commons form consists of generalized, symmetrical, red, scaly patches involving the scalp, knees and elbows, and the trunk. This form varies in intensity and may persist for life.

Sometimes, acute psoriasis is brought on by an infection like strep throat. In this case it appears in drop-like form. Although treating the bacterial infection may help clear the skin, once this kind of psoriasis appears it tends to be stubborn, and other treatments are often necessary.

Rarely, generalized redness occurs, or lakes of pus appear. These outbreaks may suddenly occur in people with the more limited lesions, perhaps associated with illness, medication, or even a bad sunburn. Or the disease may be confined to the palms of the hands and/or soles of the feet, with or without pustules. In each of these cases, targeted and intensive therapy may help, but relapses are frequent and a maintenance treatment program is usually required.

On rare occasions, psoriasis clears spontaneously, not to return for many years. Until a cure is found, however, most will need to continue some form of therapy for the rest of their lives.

What Aggravates the Disease?

In a susceptible individual, many diverse factors can bring on or aggravate psoriasis. These include:

• emotional stress

• physical injury

• allergies

• infections, particularly strep throat and HIV

• a toxic reaction to ultraviolet light (UVL)

In addition, some drugs have been shown to play a role. Medications like lithium, corticosteroids, beta-blockers, antimalarials, and nonsteroidal anti-inflammatory drugs are all possible triggers. Excessive consumption of alcohol, too, may not only worsen psoriasis but also increase the risk of mortality in moderate to severe cases.

Finally, pregnancy has been associated with psoriasis as well, but the news here is mixed. Of those with psoriasis, 50 percent improve with pregnancy, but 25 percent get worse and 25 percent are unchanged.

When Psoriasis Causes Arthritis

Generally, psoriasis only affects the skin. However, about 10 percent of people with psoriasis develop psoriatic arthritis. In this condition, psoriasis usually precedes the arthritis. Inflammation may worsen as the psoriasis intensifies. The reverse is true as well; clearing of the skin can partially or completely relieve the arthritis symptoms. This is particularly true after a Goeckerman regimen treatment (described in chapter 6) where multiple factors, rest, tar and ultraviolet light may play a role. How does the doctor decide you may have psoriatic arthritis?

• the blood factor that would indicate rheumatoid arthritis tests negative

• it affects the finger and toe joints nearest the nails

• pain and stiffness is present in the lower back

• the nails appear pitted and separated from the nail beds

• x-rays will show inflammation

Psoriatic arthritis may first affect a joint that suffered a prior injury. Rarely a severe and destructive form of the disease occurs, bringing with it deformities and disability.

Generally, managing severe psoriatic arthritis with both a dermatologist and a rheumatologist is recommended. Treatment for resistant cases of psoriatic arthritis involves the use of several of the systemic drugs discussed in chapter 7.

What Is the Underlying Cause of Psoriasis?

The exact cause of psoriasis is still not completely known, although there have been many advances in our understanding during the past decade.

For a long time, psoriasis was considered a genetically transmitted disease. Therefore, patients were frequently asked to give a family history of the condition. Indeed, statistically speaking, if one parent has the disease, there is a one in four chance that the child will develop it. If both parents have it, the probability rises to 50 percent.

Modern testing has found that genetic markers exist in some patients but are absent in others. Early onset disease — psoriasis that shows up before adulthood — tends to be not only associated with a positive family history but also more severe in effect. And yet, severe disease has been seen in patients with absolutely no family history whatsoever.

In addition to genetics, other theories propose to explain the cause of psoriasis. Relying on substantial evidence, many dermatologic investigators now believe psoriasis is a disease of the immune system that occurs in people with a genetic predisposition. They call it a T cell-mediated autoimmune disease. T cells are the blood cells responsible for immune responses. At some point, it is believed, disease-producing T cells emerge in a psoriasis-prone individual, interacting with the skin cells and causing the symptoms to emerge. Other explanations that point to the immune system require further study. (It is important to point out that the changes in psoriasis-affected skin related to the immune system affect the skin only and do not represent AIDS or any increased risk of AIDS.)

Another theory, long advocated by a few persistent dermatologists, is that certain bacteria and fungi activate psoriasis. Most have resisted this theory. However, recent studies may spark new interest in this subject, particularly the discovery that certain bacterial toxins may activate large numbers of T cells and cause them to reproduce faster.

Today, most believe that an abnormality of the T cell immune system of the skin causes psoriasis. New revelations that seem to support this possibility have resulted in an intensive search for new treatments. However, much more needs to be done before the relationship between the immune system and psoriasis is fully understood.

The cause of psoriasis may be multifactorial: a combination of things may induce it.

The Emotional Side of Psoriasis

Psoriasis hurts — not just the body, but the psyche as well. Chronic conditions like this one can cause emotional stress, social difficulties, and many other reactions. It is important to know that whatever your feelings, they are normal. There is no right or wrong way to feel about having this disease. But it is also important to recognize that how one copes with psoriasis will determine your general sense of well-being.

Our discussion of the emotional aspects of psoriasis begins with four in-depth interviews of individuals with severe psoriasis. As you read these stories, some common emotional threads will emerge. On the downside, there is denial that anything is wrong (to the point of living in a fantasy world), embarrassment at the lesions, and fear of discovery by others. Yet on a more positive note, these individuals also exhibit amazing strength, persistence, and faith in a future made better by effective treatment.

Case 1: Martha, Living in a Different World

"I was nine years old when my mother first took me to a doctor for a persistent 'rash' on my legs. When the doctor saw it, he said it couldn't be cured. As a result, my mother took me from doctor to doctor looking for an answer to my problem. I remember she would often say to me, 'Don't tell anyone.' My mother was ashamed of my skin problem.

"Even as a child I tried to deny its existence. At first it was only on my legs. Gym class at school was horrible. I was with kids who, on seeing my skin, said mean, ignorant things, sometimes even sleazy things.

"In the fourth grade, gym class was really bad. I tried my best to stay with kids who knew and accepted my condition. I learned early on how to brace myself against terse remarks. I would not allow the remarks to penetrate me; I wouldn't let them hurt me. I never told people what I had. If they asked me, I said it was 'nerves.'

"My father was anti-doctor. He would reluctantly drive me to the doctor and pay the bills, but he could not accept my problem. He said it was just poison ivy. I began to build up a shell around me and tried to deny what I had. I would make believe by telling myself that one day I would wake up and it would be gone.

"It was a drag getting up every Saturday morning to go to the doctor. My whole day was ruined. When my skin would look better my mother would say, 'I'm so glad it is cured.' Even then I somehow knew it was never going to be cured.

"I never had trouble getting boyfriends. My family and I would go to the Catskills where they had lots of sun in the summer. The boys there noticed me because I was pretty. But I always kept covered up. 'If they only knew what was under my clothing,' I thought.

"I dressed flashily but always wore pants. I would never wear a dress, shorts, or swimming suit. I always wore my hair long to cover up the lesions about my hairline. I got to the point where I would put my problem out of my mind, or at least I thought so. I would make believe it was not there. I was pulling off this charade on myself. It would work for a while.

"I always had a good job. I had to. I needed money to take care of my psoriasis. I was very vain about my appearance. I always had to look perfect — my hair, my clothes, everything. I always wanted to look good. I put on fancy clothes to delude myself. It was easy to delude.

"Sometimes I would get into real self-pity. I felt cheated. For example, when I would go to the beach, I would only leave my arms and legs uncovered. I just knew everybody was looking at me. Everyone else was in a bathing suit. If I saw someone I knew, I would turn away and pretend not to recognize him or her.

"I often felt resentment. It's a bummer, but then again I have to believe it is not the worst thing in the world. In some ways my psoriasis has made me a stronger person. I have tried to learn to live with this ugly thing. But for me that has been very hard to do.

"In some ways my disease changed the way I handled things. I never let a man stay overnight with me. When I lived in Montreal, I met this wonderful guy. When we made love, I only undressed in the dark. He never suspected or said anything about it. I would leave by four o'clock in the morning so he couldn't see me undressed in the daylight.

"The first time I ever admitted I had psoriasis was when I was working in a restaurant. It felt strange to say the word psoriasis out loud. It happened when this guy kissed my hand and said, 'What do you have on your hand?' I said 'psoriasis,' and he just laughed. Then I laughed and that was that.

"With men, if things got too complicated, I would just say 'I'm sorry' and move on so I didn't get hurt. I was hiding something and had done so for years. I just could not handle the reality of my situation and would often lie rather than face reality. Psoriasis can cripple the mind.

"I met this guy and we rented a house on Fire Island. The very first night we were together, I told him I had psoriasis and he had no problem with it. Sometimes I think I married this man to avoid the embarrassment of another summer. My marriage has been good. We have a good relationship. When we go to Hawaii, we find a secluded spot for a few days and then, when my psoriasis clears, we visit other beaches.

"When people see my psoriasis I still say it is 'nerves.' Friends would say, after knowing me for years, 'I never knew you had that.' How could they not know? Sometimes I cope by putting myself in a higher place, into a different world, so to speak. As a result, I lead a kind of double life, one in a 'make-believe' world and one in reality. I realize I have a husband and two children to consider and things are not always that bad. I still, however, cringe when I hear that word, psoriasis. To me it means ugly. For every move I make in life, I always have to consider the psoriasis. It is with me every second of every day."

Case 2: Susan, Wanting to Be Free

"My psoriasis started on my scalp when I was thirty-two years old. The first doctor I went to did a skin biopsy, which confirmed the diagnosis of psoriasis. He never told me it was an incurable disease. He also never took time to discuss my concerns and the apprehensions I had about my problem.

"At first I largely ignored it, hoping it would just go away. Then one night, in the middle of the night, I suddenly felt very warm. In the morning, when I awoke, I noticed the eruption had spread to my entire chest and back. Within a few months, it involved my entire scalp. I panicked. I couldn't cover it up on my forehead anymore. I tried to shove the disorder aside, thinking that if I was patient it would clear. I was in total denial.

"It didn't help that my husband reacted adversely to my disorder. He said it didn't bother him, but I knew better. Sexually I was careful not to reveal myself to him. I always wore nightgowns or pajamas, using the excuse that they held the medications on my skin.

"When a problem would occur in my marriage, I always interpreted it as a form of rejection because of the psoriasis. When the lesions got very red, painful, and bled, I could no longer feel comfortable, even with my husband. The lesions also made me feel like I was losing my femininity and sexuality. I began to put up a barrier between myself and my husband, as well as other members of my family.