Psoriasis is a skin condition in which inflammation in the skin, exacerbated by T-cells of the adaptive immune system (autoimmune response), causes itchy and sometimes painful rashes and lesions. The lesions develop because the skin cells grow and divide rapidly. The most common type of psoriasis is called plaque psoriasis. The plaques are dry, red and raised rashes covered by silvery-white scales. These plaques occur most commonly on the elbows, knees, scalp and lower back.
Most Psoriasis patients have mild or moderate psoriasis. Mild psoriasis means that less than 3% of the body surface area is involved, while moderate disease usually involves between 3 and 10% body surface area. Disease involving more than 10% body surface area is usually classified as severe.
Psoriasis can decrease a patient’s quality of life, and can also be associated with cardiovascular, arthritic and metabolic diseases, as well as anxiety, depression and suicide. The psoriasis itself can evolve into chronic inflammatory arthritis called psoriatic arthritis. In addition, for those with severe psoriasis there can be an increased risk of lymphoma, like cutaneous T-cell lymphoma.
Psoriasis is usually diagnosed initially in patients before age 35, but can occur at any age. There are many factors which can results in the development of psoriasis.
Some Quick Facts about Psoriasis
Psoriasis is not contagious
Psoriasis flare-ups can be triggered, and the triggers will vary between individuals
Psoriasis is an autoimmune disease
Psoriasis can have many different causes, including genetics, the environment and some medications
Psoriasis is believed to occur in up to 125 million people worldwide, and up to 8 million people in the US
Most patients with psoriasis have mild or moderate disease
Psoriasis symptoms are most commonly seen on the skin and potentially include red patches of skin with silvery scales (called plaques), small scaling spots (guttate psoriasis; more commonly seen in children), dry cracked skin that may bleed and/or may be itchy, and skin that is itchy, burning or sore. The extent of skin involvement can be very small to very large. Skin areas most commonly affected include the elbows, knees, legs, soles of the feet, palms of the hands, scalp, face and lower back.
Symptoms may also involve the nails, including thick nails or nails with pitting or ridges.
Finally psoriasis can also effect the joints – including swollen or stiff joints.
Psoriasis symptoms often flare up and then go away, often to occur again later. There may be specific triggers for flares for some individuals.
There are a number of different types of psoriasis, generally reflecting where the symptoms occur. The most common version is plaque psoriasis occurring on the elbows, knees, scalp and back.
Psoriasis Treatment Options
Treatment options for psoriasis are determined by the extent of involvement (severity) of the disease, as well as the type of disease. The major objective of psoriasis treatment is to reduce the rate that the skin cells grow and divide and to remove the scales. Generally treatments can be divided into 3 types: topical treatments, light therapy (phototherapy or photodynamic therapy) and systemic (oral or injected) medications.
Skin-directed (topical) treatments
Directed specifically to the skin to minimize systemic side effects, skin therapies can nonetheless be associated with a number of significant side effects, including increased risk of skin cancer.
Corticosteroids – steroid creams are meant to decrease inflammation and slow down cells in your skin. They may help with itching, redness and swelling. Side effects including thinning of the skin, stretch marks, striae, acne/pimples and hair growth. They should not be used on the face or genitals.
Retinoids – compounds derived from vitamin A that regulate many biological processes, including cell growth. Side effects include redness, itching, warmth of the skin, swelling, burning, scaling, and other skin irritations. Treated areas are also photosensitive and should be protected from UV light.
Vitamin D analogs – synthetic forms of Vitamin D which can slow skin growth. Mild contact dermatitis can occur, including itching, burning and erythema.
Calcineurin inhibitors – these inhibitors reduce inflammation and plaque buildup and may be used on thin skin (such as around eyes) where other topical treatments might risk damaging the eyes. They are not recommended when pregnant or breastfeeding, or if you intend to become pregnant. Long term use is associated with a potential increased risk of skin cancer and lymphoma.
Salicylic acid – available as shampoos and scalp solutions, salicylic acid may reduce the scaling of scalp psoriasis.
Tar products – coal tar is an over the counter medication that may be used to reduce scaling, itching or inflammation but it can also irritate the skin. It has a strong odor. It is not recommended for pregnant or breastfeeding women. Combination of coal tar with Ultraviolet B light therapy is known as Goeckerman therapy. Other potential tar products include anthralin, which may be used to slow skin cell growth or remove scales. It is not to be used on the skin or genitals and is known to irritate skin. Tar products are also known to stain fabrics (clothing, sheets, etc.).
Phototherapy and Photodynamic Therapy (Light Therapy)
Currently, light therapy in Psoriasis relies on the use of ultraviolet (UV) light. Because ultraviolet light is carcinogenic, its use is restricted to moderate to severe Psoriasis. Side effect include enhanced risks of skin cancers (including melanoma). Light therapy is considered a first line treatment for moderate to severe Psoriasis.
Phototherapy – can include both light therapy alone (UV A or UV B light used to destroy T-cells in a directed manner). UV B light might be used either as a broadband or narrowband light source. It is usually applied 2-3 times per week. UV B light may also be applied with a laser, to direct treatment to a specific area. In addition to the increased risk of skin cancers, other side effects can include redness, itching, dry skin and burning. Premature skin aging may also occur
Photodynamic therapy – photodynamic therapy involves the use of both a photosensitizing agent and a light source to activate the photosensitizing agent. The most commonly known approach is the use of psoralen (topically, or more commonly orally) combined with UV A light (known as PUVA). The lifetime use of PUVA is limited due to the enhanced risk of melanoma. It also can cause eye damage, dry and wrinkled skin, freckles, and increased sun sensitivity.
Generally reserved for more severe/advanced disease, systemic therapies involve whole-body exposure to the therapy either by taking it orally or by injection.
Retinoids can also be given systemically to reduce the number of skin cells. As with topical treatment, photosensitivity is a significant side effect, as well as dry skin, muscle soreness, an increase in blood lipids and an underactive thyroid gland.
Steroids might be administered directly into some lesions.
Immune modulators such as cyclosporine may be taken to suppress the immune system stop the growth and proliferation of cells. Serious side effects can occur, including diarrhea, nausea, and thrombocytopenia (low platelets).
Chemotherapy agents are used to suppress the inflammatory and immune system. Methotrexate reduces the production of skin cells and can suppress inflammation. Side effects include upset stomach, loss of appetite and fatigue. Blood tests should be done routinely while taking methotrexate to check on blood cell counts and liver function. Similarly, cyclosporine is taken to suppress the immune system, although it should not be taken for more than a year at a time, and can increase risk of infections and cancer. Blood tests should be done routinely to monitor kidney function and blood cell counts.
Biologics are generally approved for moderate and severe psoriasis for patients that have failed at least one other therapy. They may also suppress your immune system, increasing the risk of infection.
Where Soligenix Comes in
SGX302 is a SAFE photodynamic therapy using visible fluorescent light and synthetically manufactured hypericin ointment. It is designed by Soligenix as a treatment for mild to moderate psoriasis, ideally enabling patients to undergo more treatments to manage their disease while accumulating significantly fewer risks/toxicities.
Hypericin is one of the most photoactive compounds known – it is easily activated with relatively low energy light. This makes it ideal for photodynamic therapy because it can be activated with fluorescent light, instead of UV A or UV B light, which are associated with increased cancer risks.
SGX302 is currently being planned for use in a Phase 2 clinical study in psoriasis.
Helpful Psoriasis Care Resources
Information on psoriasis disease progression and treatment options is also available at the following sites: