Joint diseases are common among patients with psoriasis. Psoriatic arthritis, the most important of these, can be defined as a rheumatoid factor-negative inflammatory arthritis associated with psoriasis and has emerged as a specific disease independent from rheumatoid arthritis. Psoriatic arthritis is divided into several clinical subsets, which is helpful in differentiating it from other types of inflammatory arthritis. The prevalence of arthritis in patients with psoriasis may be far higher than the previously accepted average of 7%. In a recent study of 5,795 members of the Nordic Psoriasis Associations, the prevalence was found to be 30%. Arthritis has a significant impact on quality of life in patients with psoriasis. These factors should be recognised as they have implications for therapy, since a number of drugs can delay or stop joint damage when given in time. This also applies to the new biologic agents, although at present these therapies are generally restricted to patients non-responsive to other available drugs. Alone or in combination, the new drugs may achieve higher response rates and have better safety profiles than older therapies. However, long-term experience is still lacking and, unfortunately, the new drugs will be far from affordable by all for some time to come.

Quality of life measures are widely used in dermatology as well as in rheumatology, but there are no large studies taking arthritis into consideration when studying quality of life in psoriasis. The aim of this study was to investigate psoriasis-related quality of life in a large sample of members of the psoriasis associations from the Nordic countries including an arthritis-related evaluation. The prevalence of reported arthritis within the groups was also estimated. An Arthritis Disability Index suitable for parallel use together with Finlay's Psoriasis Disability Index was constructed. A total of 5,795 members and 702 patients seen by Nordic dermatologists rated the severity of their disease and completed the Psoriasis Disability Index formula and a Psoriasis Life Stress Inventory, and if arthritis had been diagnosed, the Arthritis Disability Index formula. Approximately 30% of all psoriatic patients, irrespective of group, received a diagnosis of arthritis either by their dermatologist or a rheumatologist. Members previously hospitalized for their disease had a higher frequency of arthritis (41%) than those without a history of hospitalization (23%). The highest prevalence of arthritis was found in Norway (33.8%). Members with arthritis exhibited greater impairment of psoriasis-related quality of life, longer disease duration, and greater self-reported disease severity for psoriasis. Important predictors for impairment of arthritis-related quality of life were pain, number of affected joints, and restriction of joint mobility. These data show, that the prevalence of arthritis in psoriasis may be significantly higher than the previously accepted average of 7%. The results demonstrate that when studying quality of life in psoriasis, arthritis and arthralgia are important independent factors to be included in the evaluation.

Though self-reported severity may be the most important predictor, further research is needed to determine factors explaining the remaining variance in psoriasis-related QOL.

We report the observation of delayed wound healing and keloid formation in three patients, following dermabrasion or Argon laser treatment administered while they were receiving isotretinoin for acne or rosacea.

Our findings confirm and extend the results of previous studies and indicate that a subgroup of psoriatics may be more psychologically reactive to their disease and its influence on everyday life. Whether this group is also physiologically more reactive to psychosocial stress remains to be investigated.