Psoriasis And The Social Connection

People with psoriasis perceive they have less social support, have difficulty expressing their feelings and have more trouble with social relationships than others, a new study shows.
Newswise — The study says these life stresses may make them more prone to outbreaks of their psoriasis.
Researchers led by Angelo Picardi, M.D., suggest in the November-December issue of Psychomatics that “psychological interventions aimed at increasing emotional awareness, fostering the security felt in close interpersonal relationships and increasing social support might help reduce” outbreaks or at least lessen their severity.
The scientists from La Sapienza University in Rome studied 33 patients with psoriasis who had a recent worsening of their symptoms and 73 patients who had other minor skin conditions. Both groups were asked about stressful events over the past year, specifically about their social and emotional lives.
Psoriasis is an inflammatory skin condition that affects about 7 million Americans. The study participants had plaque psoriasis, the most common form, which appears as patches of raised, reddish skin covered by silvery-white scales and forms most commonly on the elbows, knees and lower back.
The researchers found that, in comparison with the group that had minor conditions, the patients with a recent psoriasis outbreak had lower perceived social support, more characteristics of bottled-up emotions and higher “attachment-related anxiety.” There were no differences in their scores, however, on measures that tested experiences in close relationships.
People who are high in attachment-related anxiety tend to worry about whether their partners really love them and often fear rejection. In addition, some people are more avoidant that others. People who are high in attachment-related avoidance are less comfortable depending on and opening up to others and are reluctant to ask their partners for comfort or support.
Age, gender, education, marital status and alcohol consumption were taken into consideration when assessing patient outcomes.
“Theoretical models emphasize that these persons tend to rely more on cognition and cognitive information than on feelings and emotional information,” Picardi said. “Clearly, self-regulation is compromised both internally and externally, which may increase susceptibility to disease.
“Perceived social support is a subjective measure, but when the level is higher, it is associated with better health,” Picardi added. “Immunological processes play a major role in the pathophysiology of psoriasis.” He said that prior research has shown that stress has particular effects on the skin, including slower wound healing, greater susceptibility of skin cells and a higher propensity for inflammation.
Picardi A, et al. Stress, social support, emotional regulation, and exacerbation of diffuse plaque psoriasis. Psychomatics 46(6), 2005.

Living With Psoriasis

"People judge us on the basis of our skin — our whole culture is based on cosmetics, lotions, creams and all that," said Finkelstein, of Oakland, Calif. "With (psoriasis), there's a whole layer of psychosocial problems, feelings of embarrassment, of shame, of ultimately feeling isolated."
But these days, Finkelstein, a filmmaker, has cast off the shy persona and is sharing his story with a new documentary, "My Skin's on Fire: Living With Psoriasis." DVDs of the film can be ordered for free at www.beyondpsoriasis.com.
He said now is an ideal time to shed light on the skin disease that affects more than 5 million people because, thanks to new medications, it's no longer a disease that needs to remain hopelessly hidden.
Rather than treating the disease topically, a new class of drugs known as "biologics" and "immuno-supressants" target the internal cause — an immune system on overdrive, which leads to the visible pile-up of inflamed skin cells. Inflammation normally protects the body, but too much of it is harmful.
"Here, really in the last 2 to 3 years, they've changed the disease of psoriasis. For many years it was considered an inflammatory skin disease. Now it's known as an 'immune-mediated disease,'" he says. "They've been able to pinpoint some of the mechanisms that misfire in the immune system."
But as Finkelstein's film shows, living with psoriasis is often far more than just a bothersome condition. Its obvious symptoms — flaky, red skin — can be a tremendous mental burden as well.
In the film, Finkelstein follows the typical trajectory of dealing with psoriasis. First, small patches of flaky skin crop up, usually when a person is a young adult. Then comes the diagnosis of psoriasis. The person may feel confused, wondering where they got such a disease, but a bit of questioning often reveals that it runs in the family — a trait kept hidden from most family members. Then, the person goes through a long trial of different treatments, many of which don't work.
Thankfully, that last step has been shortened by the advent of biologic drugs, said Dr. Alan Menter, a clinical professor of dermatology at the University of Texas Southwestern Medical School in Dallas and founder of the International Psoriasis Council.
Menter, who was interviewed for Finkelstein's film, said it accurately portrays the emotional burden of the disease.
For example, when patients first come to him for medical help, they often are overweight and depressed, Menter said. Most newly-diagnosed patients are young adults.
"For example, you take a 25-year-old, standing in the mirror seeing these crusted patches all over his or her body. They're trying to go out and get a date and it's crushing. They can hide it with clothing but that can't hide it from themselves or when they relationship starts becoming intimate," he said.
But Menter and Finkelstein are both optimistic that this will be less of a problem in the coming years, as more people are treated with medicines that truly help quell the disease.
"Right now I think there are something like 40 new drugs," Finkelstein said. "The future looks very bright for all of us who have suffered for so many years. I think it's a very good time to be talking about psoriasis."

What is Psoriasis?

Psoriasis is a common immune-mediated chronic skin disease that comes in different forms and varying levels of severity. Most researchers now conclude that it is related to the immune system (psoriasis is often called an "immune-mediated" disorder).It is not contagious. In general, it is a condition that is frequently found on the knees, elbows, scalp, hands, feet or lower back. Many treatments are available to help manage its symptoms. More than 4.5 million adults in the United States have it. Between 10 percent and 30 percent of people with psoriasis also develop a related form of arthritis, called psoriatic arthritis.

Psoriasis and the T-Cell Connection

Scientists believe that certain white blood cells called T lymphocytes (T cells) play an important role in psoriasis. "And the disease has a genetic component," says Lindstrom. In about one-third of psoriasis cases, there is a family history of the disease.
T cells circulate throughout the body, orchestrating the immune system's response to foreign invaders like bacteria or viruses. In people with psoriasis, the defective T cells are overactive and migrate to the skin as if to heal a wound or ward off an infection. This process leads to the rapid growth of skin cells, triggering inflammation and the development of lesions.
Both the environment and genetics may play a role in the development of psoriasis. "In genetically predisposed children, psoriasis can be triggered by a strep or other infection," says Lindstrom. That's what happened to author John Updike. After an attack of measles at the age of 6, Updike developed psoriasis "in all its flaming scabbiness from head to toe," as he later described it in his memoir, Self-Consciousness.

PSORIASIS: CURE OR REMISSION

While the disease never goes away, the symptoms of psoriasis subside for a while (remission) and then return (flare-up, or reactivation). Remission can last for years in some people; in others, flare-ups occur every few weeks. Certain triggers, such as stress and seasonal changes, can reactivate psoriasis. "Certain drugs may also exacerbate it," says Lindstrom, including lithium, prescribed for bipolar disorder (also called manic-depressive illness), beta-blockers used to treat high blood pressure, and antimalarial drugs.

Arthritis Drug Treats Psoriasis

A drug for rheumatoid arthritis can relieve the suffering of patients with moderate to severe psoriasis for a year, researchers said on Friday.
They found that infliximab, which is marketed under the name Remicade by Johnson & Johnson in the United States and by Schering-Plough Corp in other markets, improved symptoms of the chronic skin condition that affects 2 percent of the population in western countries.
"This is the first study to show that the very rapid and dramatic improvement that you see with psoriasis can, in the majority of patients, be maintained over at least the medium term -- over the course of a year," said Professor Christopher Griffiths, of the University of Manchester in England.
Previous trials have only looked into the impact of the drug on psoriasis over a short period of about 12 weeks.
The study published in The Lancet medical journal also showed patients saw a significant improvement in one of the most disturbing features of psoriasis: nail disease.
"Up until now it has been extremely difficult to treat," Griffiths told Reuters.
He and his colleagues compared the effects of the intravenous treatment to a placebo, or dummy drug, on 378 patients with the illness.
Each patient was given three intravenous infusions of the drug or a placebo over six weeks and then every 8 weeks for nearly a year. After less than 3 months on the treatment, 80 percent of the patients showed at least a 75 percent improvement, compared to 3 percent in the placebo group.
By the end of the trial, the drug completely cleared the skin condition in a quarter of patients but no one in the placebo group had the same result.
"Some of the patients were improved to the extent that they had no psoriasis and there was no impairment of their quality of life. So this is the best result you could possibly aim for with a treatment for psoriasis," said Griffiths.
"Compared with the other available treatments, it does work extremely effectively and extremely quickly."
The scientists said none of the patients given the drug had any serious side effects. But they stressed that the treatment is not a cure. It is likely patients would have to be on a long-term maintenance programme.
Psoriasis, an immune mediated disease, can develop at any age but it occurs most commonly before the age of 40. Psoriasis patches can also show up on the fingernails and toenails. About 15 percent of patients also suffer from arthritis linked to the condition.
European regulators recently approved infliximab for the treatment of psoriasis but the drug has not yet been approved for the skin condition in the United States.
The drug is also used as a treatment for Crohn's disease, an inflammatory bowel condition.

TREATING PSORIASIS WITH LIGHT THERAPY

Exposing the skin to ultraviolet (UV) light--either from the sun or an artificial source--sets off a biological process that kills T cells, which slows the buildup of skin cells and reduces inflammation.
Light boxes that emit UV light to treat moderate-to-severe psoriasis and other skin diseases are medical devices that require licensing by the FDA. A person steps into the light box, which is about the size of a telephone booth, while lamps direct the light onto the body.
"Treatment with these devices is complex," says Richard Felten, an FDA chemist and senior medical device reviewer. The physician must determine an individual's sensitivity to UV and adjust the light emissions for the most effective treatment with the least risk of side effects, he says. Side effects may include burning, darkened skin, premature aging, and skin cancer. Three to five treatments per week for several weeks or months may be needed to get the psoriasis under control, followed by weekly maintenance treatments.
Light therapy, or phototherapy, is usually done in the physician's office or a medical facility that has the devices, says Felten. "The FDA has cleared some devices for home use under certain conditions and with a doctor's prescription," he says. Home devices include handheld devices for scalp psoriasis and stand-alone light boxes for other areas of the body.
Light therapy usually involves a short wavelength of ultraviolet light, called UVB. For people with resistant moderate-to-severe psoriasis, a combination of an oral or topical drug called psoralen and a longer wavelength ultraviolet A (UVA) light is used. This treatment is called "psoralen plus UVA" (PUVA).
"Psoralen makes the patient more sensitive to the UVA," says Lindstrom, "so once they've taken a dose of psoralen, a smaller dose of UVA is needed to treat them." Patients must be very careful to protect both skin and eyes for 24 hours after psoralen use to prevent damage, she says.
The FDA has also approved a special type of laser, an excimer laser, as a phototherapy device to treat mild-to-moderate psoriasis. "These lasers can deliver a much more controlled beam of light to small areas of the affected skin," says Felten.

Systemic Psoriasis Treatments

The FDA has approved oral and injected drugs that circulate throughout the body to treat psoriasis that is moderate, severe, or disabling. These systemic drugs are very powerful, and while some may be used continuously, others can only be used for a limited time because of their severe side effects. Once a drug is discontinued, the psoriasis may reactivate. The risk of birth defects prevents many systemics from being taken by pregnant women or women planning to become pregnant.
Systemic drugs that may be prescribed for psoriasis include acitretin, methotrexate, cyclosporine, and biologics, which are drugs made from proteins of living cells. Methotrexate, cyclosporine, and the biologic drugs are immunosuppressants, meaning they lower the body's normal immune response. "These drugs suppress the immune cells that cause psoriasis, but they don't distinguish these cells from the immune cells that protect our body from infections," says Elektra Papadopoulos, M.D., an FDA dermatologist.
Acitretin, a retinoid that is given orally for severe psoriasis, helps normalize the growth of skin cells. One of the side effects is raised fat (lipid) levels in the blood, and people taking this drug must get regular blood tests to monitor their cholesterol and triglyceride levels.
Methotrexate and cyclosporine slow the growth of skin cells. Methotrexate, taken orally or by injection, is also a chemotherapy drug for cancer patients. Cyclosporine, taken orally, was first approved to prevent organ rejection in transplant recipients. People using either of these drugs must be closely monitored and should use them only for short periods of time because of serious, potentially fatal, side effects.
Biologics are the newest systemic psoriasis treatments. Since 2003, the FDA has licensed three biologics to treat moderate-to-severe plaque psoriasis: Amevive (alefacept), manufactured by Biogen Inc.; Raptiva (efalizumab), made by Genentech Inc.; and Enbrel (etanercept), marketed by Amgen Inc. and Wyeth Pharmaceuticals. Enbrel was first licensed in 2002 to treat the arthritis associated with psoriasis, and in 2004 to treat psoriasis itself.
"All are immunosuppressive and have different proposed mechanisms," says Papadopoulos. Amevive simultaneously reduces the number of immune cells, including T cells, and inhibits T-cell activation. Raptiva inhibits the activation of T cells and the migration of those cells across blood vessels and into tissues, including the skin.
Enbrel inhibits the action of an inflammatory chemical messenger in the immune system called tumor necrosis factor-alpha (TNF-alpha), which is believed to play a role in both the skin and the joint symptoms of psoriasis.
All three biologics are injected. The FDA has licensed Amevive to be given in a physician's office, either injected into the muscle or into a vein (intravenously). It's a once-a-week treatment for 12 weeks; further treatments may be given after a waiting period.
The FDA has licensed Raptiva and Enbrel for home treatment. People can inject themselves with Raptiva under the skin once a week or with Enbrel once or twice a week. Both drugs are recommended for continuous use to maintain results.
Since biologic drugs are immunosuppressants, they may carry an increased risk of infection and cancer. Rare but serious effects have also included blood abnormalities and autoimmune diseases such as lupus. Other side effects are flu-like symptoms and pain and inflammation at the injection site.
Some dermatologists prescribe biologics alone for psoriasis or in combination with topical treatments. Leonardi says when he prescribes biologics, "I don't have to resort to adding other systemic therapies such as methotrexate, cyclosporine, acitretin, or phototherapy."
"Biologics are an alternative treatment to some of the traditional therapies," says Papadopoulos.
"Now we need to get the expense down," says Leonardi, who has patients who pay $30,000 per year on drugs to treat psoriasis.
Bird feels fortunate that her insurance company covers most of the expense of Enbrel, which is prescribed for both her psoriasis and psoriatic arthritis. Because of the arthritis pain, she has used a cane to help her walk and has had surgery on her wrist to correct some of the arthritis damage. Although Enbrel has been less effective over time for the psoriasis, she says, it's reduced her arthritic pain by about 95 percent. "I can jog down to the corner to chase after the dog," she says. "And last summer, I went hiking with my children in Colorado."

Reducing Psoriasis Treatment Risks

Biologics, other systemic drugs, and phototherapy are powerful treatments with increased risks, says Lindstrom.
Biologics may raise the risk for developing cancer and serious bacterial or fungal infections that spread throughout the body (sepsis).
Cyclosporine can damage the kidneys, methotrexate puts the liver and lungs at risk, and phototherapy can cause skin cancer. To reduce these risks, doctors often put patients on "rotational therapy." "The thought is by moving from one therapy to another therapy over time, the risk to any individual organ is reduced," says Lindstrom.
"We also try to choose a drug with an appropriate benefit-risk ratio," she says. For mild psoriasis, a topical steroid may be appropriate. For more severe disease, where it becomes impractical to apply topicals over a large surface area several times a day, a patient may need a systemic treatment.
Most of the highly effective treatments for psoriasis affect the immune system in some way. For steroid drugs, which have been around for more than 50 years, the risks are well known. But less is known about the long-term side effects of newer drugs, such as the biologics. The safety and side effects of biologics and other immune-suppressing drugs to treat psoriasis continue to be monitored by drug manufacturers and the FDA

The Future of Psoriasis Treatments

Researchers continue to look for reasons why immune cells overreact and what genes may be responsible for psoriasis, hoping to find better treatments, and eventually a cure. Psoriasis research is aided by the visibility of the symptoms on the skin.
"You can see the disease," says Leonardi. "You don't have to do invasive testing to see the effects of therapy." Psoriasis research has a "tremendous spillover into other fields besides dermatology," he adds. "There is a huge need for drugs to suppress the immune system without the side effects."
Multiple sclerosis, Crohn's disease, rheumatoid arthritis, and type 1 diabetes are just a few of the diseases that may also benefit from psoriasis research.

Finding the Right Treatment for Psoriasis

You may need to try different treatments before you find one that works well for you. It is important to discuss your treatment and progress with your doctor.
A recent study found that education, stress reduction, and muscle relaxation training can be beneficial to many people with psoriasis. Adding these elements to a treatment plan can reduce disability, anxiety, and stress related to dealing with psoriasis.
Treatments for psoriasis have potential side effects. People with moderate or severe psoriasis may need treatment for the rest of their lives. Many doctors will recommend that treatments be changed or rotated after a certain period of time to improve treatment effectiveness and reduce side effects.

Treating Psoriasis: Amevive

AMEVIVE is the first biologic approved by the FDA for the treatment of moderate to severe chronic plaque psoriasis in adults who are candidates for systemic therapy or phototherapy. AMEVIVE is a prescription medication that is injected by your doctor (15 mg IM, into the muscle) once a week, for a total of 12 doses.

Amevivie is not without side effects.
The most serious adverse reactions were:
Lymphopenia (see WARNINGS)
Malignancies (see WARNINGS)
Serious Infections requiring hospitalization (see WARNINGS)
Hypersensitivity Reactions (see PRECAUTIONS, Allergic Reactions)
Commonly observed adverse events seen in the first course of placebo-controlled clinical trials with at least a 2% higher incidence in the AMEVIVE®-treated patients compared to placebo-treated patients were: pharyngitis, dizziness, increased cough, nausea, pruritus, myalgia, chills, injection site pain, injection site inflammation, and accidental injury. The only adverse event that occurred at a 5% or higher incidence among AMEVIVE®-treated patients compared to placebo-treated patients was chills (1% placebo vs. 6% AMEVIVE®), which occurred predominantly with intravenous administration.

Basic Treatment Protocol For Psoriasis

Treatment of psoriasis is determined by the location, severity and history of psoriasis in each individual. There is no one method of treatment, for each person with psoriasis may respond differently. One main objective of treatment is to slow down the more rapid than usual growth rate of the skin cells. The rapid growth rate of skin cells causes the red, scaly psoriasis patches. The underlying cause of this increased skin growth is not yet known. For patients with minimal psoriasis, therapy is limited to topical medications that are drugs applied to the skin. For patients with moderate to widespread psoriasis, topical treatments are often combined with ultraviolet light therapy. Either sunlight or artificial ultraviolet light therapy can be used. If topical and ultraviolet light therapy are not effective, or are not practical, systemic or oral medications can be used. These may be combined with ultraviolet light therapy, the so-called photo-chemotherapy or PUVA therapy. In severe cases and unresponsive cases of psoriasis, there are oral medications that slow down the growth rate of skin which are helpful. These drugs can have significant side effects and have to be used with the proper safeguard and caution. Even these strong drugs do not cure psoriasis but only help to control the disease.

Symptoms of Psoriasis

Individuals with psoriasis experience symptoms such as itching, cracking, stinging, burning, or bleeding. Lack of sunlight and low indoor humidity in the winter months can cause the psoriasis symptoms to worsen. The skin is most likely to crack at the joints where the body bends, or in areas where the individual scratches. Scratching should be strictly avoided, because it can cause bleeding and infection. Psoriasis has also been known to cause pits or dents to form in fingernails and toenails. There is also the possibility that the soft tissue inside the mouth and genitalia can be affected. In some cases, psoriasis will cause joint inflammation that produces arthritis symptoms. This condition is called psoriatic arthritis.People with psoriasis may notice that there are times when their skin worsens, then improves. Conditions that may cause flare-ups include changes in climate, infections, stress, and dry skin. Also, certain medicines, most notably beta-blockers, which are used in the treatment of high blood pressure, and lithium or drugs used in the treatment of depression, may cause an outbreak or worsening of the disease.

General Definition of Psoriasis

Psoriasis is a chronic scaling skin. It may range from just a few spots anywhere on the body to large areas of involvement. It is not contagious or spread able from one part of the body to another or from one person to another. There is no blood test to diagnose psoriasis. The diagnosis is made by observation and examination of the skin. Sometimes microscopic examination of the skin (biopsy) is helpful where the changes are not typical or characteristic. The exact cause of psoriasis is unknown, but hereditary and genetic factors are important. Psoriasis runs in families. This does not mean, however, that every child of a parent with psoriasis will develop psoriasis, but it is common that somewhere down the line psoriasis will appear in families. Psoriasis is not caused by allergies, infections, dietary deficiencies or excesses, or nervous tension.

The Appearance of Scalp Psoriasis

Scalp psoriasis occurs in at least half of all people with psoriasis. It can range from very mild with fine scaling to very severe with thick, crusted plaques. Scalp psoriasis may appear as lesions that extend from the hairline onto the forehead and the nape of the neck. It is common for the psoriasis to appear behind the ears. Scalp psoriasis usually accompanies plaques in other areas of the body. Scalp psoriasis scales appear powdery with a silvery sheen. Possible causes of scalp psoriasis include: scalp treatments and severe psoriasis can both cause temporary hair loss; itching, picking and scratching lesions can worsen the psoriasis by causing a Koebner phenomenon (psoriasis appearing on the site of skin injuries).

Treating The Different Types of Psoriasis

There are five different types of psoriasis. The most common form of psoriasis is called "plaque psoriasis," which is characterized by well-defined patches of red, raised skin. About 80 percent of people with psoriasis have this type. Plaque psoriasis can appear on any skin surface, although the knees, elbows, scalp, trunk and nails are the most common locations. The other types of psoriasis are: Guttate described as small, red, individual drops on the skin. Inverse psoriasis is smooth, dry areas of skin, often in folds or creases, that are red and inflamed but do not have scaling Erythrodermic psoriasis is characterized as periodic, widespread, fiery redness of the skin. Pustular psoriasis which involves either generalized, widespread areas of reddened skin, or localized areas, particularly the hands and feet (palmo-plantar pustular psoriasis).Typically, people have only one form of psoriasis at a time. Sometimes two different types can occur together, one type may change to another type, or one type may become more severe. For example, a trigger may convert plaque psoriasis to pustular.

Large Plaque and Small Plaque Parapsoriasis

Current terminology of parapsoriasis refers to 2 disease processes that are caused by T-cell–predominant infiltrates in the skin. These disease processes are large plaque parapsoriasis and small plaque parapsoriasis.
As the nomenclature and description of the disease spectrum under the descriptive term parapsoriasis evolved, the primary focus has been on the distinction of whether the disorder progresses to mycosis fungoides (MF) or cutaneous T-cell lymphoma (CTCL). Small plaque parapsoriasis is a benign disorder that rarely if ever progresses. Large plaque parapsoriasis is more ominous in that approximately 10% of patients progress to CTCL. Controversy exists in the classification of large plaque parapsoriasis because some think it is equivalent to the earliest stage CTCL, the patch stage.
The duration of parapsoriasis can be variable. Small plaque disease lasts several months to years and can spontaneously resolve. Large plaque disease is chronic, and treatment is recommended because it may prevent progression to CTCL.
Pathophysiology: The initiating cause of parapsoriasis is unknown, but the diseases likely represent different stages in a continuum of lymphoproliferative disorders from chronic dermatitis to frank malignancy of CTCL.

Small plaque parapsoriasis likely is a reactive process of predominantly CD4+ T cells. Genotypic pattern observed in small plaque parapsoriasis is similar to that observed in chronic dermatitis, and the pattern of clonality of T cells is consistent with the response of a specific subset of T cells that have been stimulated by an antigen. Multiple dominant clones can be detected by polymerase chain reaction (PCR) of T-cell receptor gene usage, which supports a reactive process. Lymphocytes do not show histologic atypia to suggest malignant transformation. Southern blot analysis of T-cell receptor genes from parapsoriasis does not identify a dominant clone of T cells.
Some physicians believe that small plaque parapsoriasis is an abortive T-cell lymphoma; however, no clear distinguishing evidence, such as genetic changes observed in other malignancies, exists to support this contention. Nevertheless, a hint to the verity of this hypothesis is the recent identification of increased telomerase activity in T cells from CTCL at low-grade stages, high-grade lymphoma, and in parapsoriasis, which is activity not exhibited in normal T cells. A better understanding is likely to develop from further molecular characterization.

Large plaque parapsoriasis is a chronic inflammatory disorder, and the pathophysiology has been speculated to be long-term antigen stimulation. This disorder is associated with a dominant T-cell clone, one that may represent up to 50% of the T-cell infiltrate. If the histologic appearance is benign, without atypical lymphocytes, classification of large plaque parapsoriasis is made. If atypical lymphocytes are present, many would classify such patients as having patch stage CTCL.

Pityriasis Lichenoides

Pityriasis lichenoides variants describe scaly dermatoses with necrotic papules that are clinically and histologically different from parapsoriasis. These diseases generally are benign and undergo spontaneous resolution.

Pityriasis lichenoides is a rare cutaneous disorder of unknown etiology. Pityriasis lichenoides encompasses a spectrum of clinical presentations ranging from acute papular lesions that rapidly evolve into pseudovesicles and central necrosis (pityriasis lichenoides et varioliformis acuta or PLEVA) to small, scaling, benign-appearing papules (pityriasis lichenoides chronica or PLC). Although historically, the term Mucha-Habermann disease has referred only to PLEVA, the term applies broadly to the entire spectrum of disease including PLC. A rare febrile ulceronecrotic variant has been reported, which is a severe form of PLEVA with high fever and marked constitutional symptoms. Lesions may self-involute and resolve completely over weeks, or new lesions occasionally may appear in crops, waxing and waning spontaneously for months to years thereafter.

Mucha-Habermann disease is not a vasculitic process despite reports of immunoglobulin and complement deposition in vessels. Fibrin is not present in the walls of vessels, and thrombi are not found in the lumen. A cell-mediated mechanism has been proposed based on a T-lymphocytic infiltrate with a cytotoxic/suppressor phenotype, diminished epidermal Langerhans cells, and a reduction of the CD4/CD8 ratio. Mucha-Habermann disease is not a lymphoproliferative disorder. CD30 (Ki-1) cells, which are associated with large cell lymphoma, have been identified in the infiltrate of both lymphomatoid papulosis and Mucha-Habermann disease, leading some authors to view this as a self-limited self-healing lymphoproliferative disease.

What is Parapsoriasis?

Parapsoriasis describes a group of cutaneous diseases that can be characterized by scaly patches or slightly elevated plaques that have a resemblance to psoriasis, hence the nomenclature. However, this description includes several inflammatory cutaneous diseases that are unrelated with respect to pathogenesis, histopathology, and response to treatment. Because of the variation in clinical presentation and a lack of a specific diagnostic finding on histopathology, a uniformly accepted definition of parapsoriasis remains lacking.
In 1902, Brocq initially described 3 major entities that fit the description:
Pityriasis lichenoides (acuta and chronica)
Small plaque parapsoriasis
Large plaque parapsoriasis (parapsoriasis en plaque)