Clinical applicability of T-cell interferon-a release assay for tumour necrosis factor-a inhibitor therapy in severe psoriasis.

Many studies have found that screening and treatment of latent tuberculosis (TB) before starting treatment with tumour necrosis factor (TNF)-a inhibitors reduces associated TB infections. The new T-cell interferon-a release assay (TIGRA), is more specific and sensitive for detection of latent TB compared with the tuberculin skin test (TST). We report results of TIGRA in our first 63 patients commencing TNF-a inhibitors for severe psoriasis. Of the 63 patients, 5 (7.9%) had a positive TIGRA result and were started on treatment for latent TB. We found that the only risk factor for TB associated with a positive TIGRA was a history of travel to countries with high TB incidence. To our knowledge, this is the first study to identify the background risk (7.9%) of latent TB in an endemic UK population. This result emphasizes the importance of TIGRA testing to reduce the risk of TB in patients treated with TNF-a inhibitor.

Treatment of recalcitrant plantar warts with imiquimod.

Myrmecia are viral warts that result from the coalescence of plantar or palmar warts into large plaques. Treatment of these warts involves physical or chemical destruction of the verrucae, potent keratolytics or immunotherapy. Imiquimod 5% cream is a novel topical immunomodulator that has been used successfully in the treatment of genital and common warts. We report its successful use in a 35-year-old immunocompetent man who had had resistant plantar warts for 15 years.

Giant bathing trunk naevus with lymphadenopathy and unusual pathology.

Giant congenital melanocytic naevi remain a challenge to clinicians and histopathologists with respect to observation for malignant change and interpretation of histology findings, respectively. We report a 5-year-old boy with a giant bathing trunk naevus who, after multiple previous skin biopsies, developed lymphadenopathy. Biopsy from the lymph nodes demonstrated collections of naevomelanocytes within the lymph node. Interpretation of these findings and subsequent management is discussed.

Outcome of facial rashes with non-specific histological features: a long-term follow-up of 64 cases.

Facial inflammatory dermatoses can be difficult to diagnose in their early stages; skin biopsy may help but often shows indeterminate features. The aims of our study were to identify patients presenting with a facial dermatosis requiring skin biopsy, in whom the initial histological features were classified as "non-specific", to determine the eventual diagnostic outcome, and to attempt to identify subtle early histologic features. We located 79 such cases with indeterminate histology from 45,000 dermatopathology reports 1972-1987. The original biopsies were assessed and scored using a check-list of 20 features and the patients' case-records up to 1992 were examined. Follow-up information was available in 64 cases and an eventual clinical diagnosis was made in 54 (84%) of these; the commonest diagnoses were rosacea (26%), chronic discoid lupus erythematosus (24%) and seborrheic or unclassified dermatitis (17%). Histological differences were seen in the original biopsies of these three diagnostic categories, although none was predictive. We conclude that clinical follow-up leads to the diagnosis of most facial rashes initially showing "non-specific" histology.

Hepatic cytochrome P450 CYP2C activity in psoriasis: studies using proguanil as a probe compound.

Retinol and proguanil are metabolised by the same family of hepatic cytochrome P450, i.e. CYP2C. We used proguanil as a probe to study CYP2C activity, and by implication retinol metabolism, in psoriasis. In vitro studies showed that retinol competitively inhibited the hepatic metabolism of proguanil to cycloguanil. Proguanil metabolism was assessed in 82 patients with chronic plaque psoriasis. Following proguanil orally (200 mg), urine was analysed for proguanil and cycloguanil. A proguanil to cycloguanil ratio < 1 signified extensive metabolism and a ratio > 10 poor metabolism. A wider range of ratios was observed in psoriasis than previously reported for normal subjects. The proguanil to cycloguanil ratio was assessed in 10 cases each of know severe and mild psoriasis. Low CYP2C activity was associated with severe psoriasis, poor metaboliser status occurring in 50% of the severe group, but in none of the mild cases, p < 0.01. These findings may indicate differences in retinoid metabolism in psoriasis.