News in brief: UVB therapy, pain relief, photodynamic therapy

Patients with high skin types photoadapt at about the same rate as those with low skin types during narrowband UVB therapy, researchers have found.

UVB therapy in high and low skin types
Patients with high skin types photoadapt at about the same rate as those with low skin types during narrowband UVB therapy, making it suitable for all skin types, regardless of minimal erythema dose (MED), according to this UK study.

The researchers studied 352 patients with psoriasis of skin types I to IV who were having twice-weekly NB-UVB. Patients with higher skin types tended to have higher MEDs, but by the 20th session, about 60% of patients had developed erythema regardless of starting dose. Among them, the number of treatments before erythema occurred did not significantly differ between skin types.

The researchers conclude that differences in skin type or MED are not associated with clinically important differences, in terms of erythema, using a standard 70/20% NB-UVB twice-weekly regimen.
J Invest Dermatol 2006; 126: 1256-63

Pain relief with combined gels
The pain of erythromelalgia can be effectively managed by using a combination of amitriptyline and ketamine gels, according to this case study. Treatment of the syndrome, characterised by attacks in which the affected limbs become bright red, hot and extremely painful, is difficult and often unsuccessful.

In this case, a 17-year-old woman had a 2-year history of increasingly frequent episodes of erythromelalgia, involving her hands, feet and lower legs. Aspirin, misprostol and gabapentin had all failed to help, although lidocaine patches had been fairly helpful.

However, a combination of 1% amitriptyline and 0.5% ketamine gels applied twice daily produced significant relief after just 2 days, and she estimated that her symptoms had improved by 90%. She slept through the night for the first time in 2 years. The authors have since replicated this success in 4 other severely affected patients.
Arch Dermatol 2006; 142: 283-6

Ambulatory photodynamic therapy
Ambulatory photodynamic therapy is a new concept, but a group of researchers at the University of Dundee suggest that it could lead to more treatment being carried out in the patient's home.

Photodynamic therapy has been shown to be effective in treating Bowen's disease, superficial basal cell carcinoma and actinic keratosis in an outpatient setting. But the feasibility of delivering the treatment using a portable device was the issue being examined here.

In the study, a prototype array of 37 AlGaInP diodes with a diffuser, driven by a battery pack, was designed and constructed. Five patients with Bowen's disease were  treated with the prototype unit in the local hospital dermatology photodynamic therapy suite, receiving 2 treatments at a 4-week interval. Four of the 5 patients were clear at an average 9-month follow-up. Pain was classified as none or mild in 80% of the treatments and moderate in the rest.

The authors of the study say that there are many potential benefits of ambulatory photodynamic therapy, including the possibility of a much higher patient throughput, and this pilot project provides early promising data on the safety and efficacy of the approach.
Br J Dermatol 2006; 154: 747-50

Laser treatment for melanocytic naevi
Congenital melanocytic naevi (CMN) are found in 1% of newborn babies. The naevi are often small, less than 5cm in diameter, and pale brown. But giant CMN are often disfiguring and the risk of malignancy is thought to be higher than for the other smaller congenital naevi.

Ten children with CMN were treated here with erbium:YAG laser resurfacing in the first weeks of life. Treatment was well tolerated by all of the children and the immediate results were good. At a follow-up ranging from 3-36 months, the results were maintained, with no or minimal repigmentation, in 8 out of 10 patients.

Minimal side-effects were seen, such as post-operative pain, bleeding and scar formation. Post-operative histopathology showed disappearance of heavily pigmented cells in the upper part of the dermis. This makes erbium:YAG laser resurfacing an effective way of ablating CMN with minimal scarring and post-operative complications. Br J Dermatol 2006; 154: 889-95

Abnormal lipids in psoriasis
Lipid abnormalities in patients with psoriasis seem to be genetic rather than acquired, say the autors of this study, which shows that they are present at the onset of the disease.

Psoriasis has been associated with increased cardiovascular morbidity, although the underlying mechanisms remain unclear. This study looked at 200 patients who had their lipid profiles assessed within 12 months of their first psoriatic lesions and compared with a matched control group with no psoriasis.

Psoriasis patients had significant lipid abnormalities, particularly higher cholesterol concentrations in the very low density lipoprotein and high density lipoprotein fractions. The differences remained after adjustment for established environmental risk factors, but their significance in relation to cardiovascular risk is uncertain, say the authors. Only a follow-up study can clarify whether the lipoprotein alterations contribute to the increased risk of cardiovascular events associated with psoriasis.
J Am Acad Dermatol 2006; 54: 614-21

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