Small Versus Large Plaque Parapsoriasis

• Parapsoriasis is classified as either small plaque or large plaque. Small plaque parapsoriasis (SPP) skin lesions usually remain smaller than 5 cm. SPP is generally asymptomatic but might cause dry skin. Typical treatment is a mild to mid-potency topical steroid ointment or lotion. Large plaque parapsoriasis (LPP) is more serious, with lesions larger than 6 cm, and is more likely to develop into skin cancer. Treatments include stronger steroid creams and application of topical nitrogen mustard or topical carmustine. Topical nitrogen mustard and topical carmustine are both chemotherapy agents. Side effects of nitrogen mustard include allergic reaction, itching, rash and darkening of the skin (hyperpigmentation) and resolve when treatment is discontinued. Topical carmustine can cause allergic reaction, hyperpigmentation, the formation of small, dilated blood vessels around the site of application (telangiectasias) and can lower the count of white and red blood cells. Most side effects disappear when the patient stops using carmustine, but telangiectasias and hyperpigmentation can be permanent.
  
  

Psoralen and Long-wave Ultraviolet Light A Phytotherapy

• Psoralen and long-wave ultraviolet light A (PUVA) shows promise in managing and eliminating large plaque parapsoriasis. The therapy is most effective in conjunction with radiation during the earliest stages of disease. A study conducted by the Department of Dermatology, Sahlgrenska University Hospital in Göteborg, Sweden, found that PUVA combined with limited radiation generated remission in 22 of the 24 patients involved in the study. The patients who had only LPP that hadn't progressed to skin cancer maintained remission for at least 18 years with one treatment. Those who had developed mycosis fungoides (first-stage CTCL) required multiple treatments, but their disease didn't progress and remission lasted three to 18 years. Two patients with advanced CTCL died during the study. Side effects of PUVA include nausea, vomiting, itching and skin irritation at the treatment site.
  
  

NB-UVB Phytotherapy

• Narrow band (311 nm) ultraviolet B (NB-UVB) phytotherapy are safe and effective to manage SPP. Researchers at the Department of Dermatology, University of Munich, Germany, used NB-UVB to treat 16 patients with SPP in 1996. Initial remission lasted approximately 29 weeks, but after an average of 32 treatments, all patients had full remission. NB-UVB has fewer side effects than PUVA and is the preferred method for treating SPP when steroids prove ineffective or there are multiple lesions.