Replacement of routine liver biopsy by procollagen III aminopeptide for monitoring patients with psoriasis receiving long-term methotrexate: a multicentre audit and health economic analysis

BACKGROUND

Patients receiving long-term methotrexate for psoriasis are at risk of developing hepatic fibrosis. Repeated liver biopsy has long been regarded as the only reliable method of detecting this and it is still recommended by the American Academy of Dermatology (AAD). More recently, monitoring by serum procollagen III aminopeptide (PIIINP) measurement (Orion Diagnostica, Espoo, Finland) has been advocated as a means of significantly reducing the need for liver biopsy.

OBJECTIVES

To assess the validity of guidelines developed in Manchester for the use of PIIINP to monitor patients with psoriasis receiving long-term methotrexate; to assess the anticipated benefits to patients of introducing this change in practice, including reduction in requirement for liver biopsy; and to determine the impact of its introduction on healthcare costs.

METHODS

A multicentre audit was conducted over a 24-month period to compare the healthcare costs and outcomes of two intervention groups from centres where serial PIIINP measurement was employed with those of two control groups from centres in which AAD guidelines were followed.

RESULTS

A sevenfold reduction in the need for liver biopsy was observed in the two intervention groups (n = 166; 0.04 and 0.02 biopsies/patient/year, respectively) compared with the two control groups (n = 87; 0.26 and 0.30 biopsies/patient/year, respectively). Abnormalities of sufficient severity to influence management were identified in one in five patients biopsied in the main intervention group compared with one in 16 in the control groups. The overwhelming majority of patients surveyed expressed a preference for being monitored by methods that would minimize the need for liver biopsy. The adoption of PIIINP for monitoring would result in significant cost savings.

CONCLUSIONS

This audit has shown that patients managed by the Manchester protocol using serial PIIINP measurement and selective liver biopsy were not disadvantaged in comparison with those managed according to AAD guidelines; they were subjected to sevenfold fewer liver biopsies without evidence that important liver toxicity was missed in the process. If PIIINP monitoring were widely adopted, methotrexate would become a more acceptable option for many patients who are dissuaded from considering it because of the threat of repeated liver biopsy; it would also result in significant savings to the healthcare budget.

Exacerbation of presumed chronic actinic dermatitis by cockpit visible light in an airline pilot with atopic eczema

Chronic actinic dermatitis (CAD) is a persistent ultraviolet radiation- or visible light-induced eczema of predominantly the exposed areas of usually elderly people. We now present the case of a young pilot with atopic eczema who developed CAD, regularly exacerbated by exposure to visible light through his aircraft cockpit window.

Scytalidium dimidiatum causing recalcitrant subcutaneous lesions produces melanin

Scytalidium dimidiatum is a pigmented dematiaceous coelomycete that typically causes chronic superficial skin diseases and onychomycosis, as well as deeper infections, such as subcutaneous abscesses, mycetoma, and even fungemia in immunocompromised patients. A second species, Scytalidium hyalinum, has hyaline hyphae and arthroconidia and is considered by some authors to be an albino mutant of S. dimidiatum. This study aimed to confirm the presence of melanin or melanin-like compounds (which have been previously implicated in the virulence of other fungal pathogens) in S. dimidiatum from a patient with multiple subcutaneous nodules. Treatment of the hyphae and arthroconidia with proteolytic enzymes, denaturant, and concentrated hot acid yielded dark particles, which were stable free radicals, consistent with their identification as melanins. Extracted melanin particles from S. dimidiatum cultures were labeled by melanin-binding monoclonal antibodies (MAbs) from Sporothrix schenckii, Aspergillus fumigatus, and Cryptococcus neoformans. Lesional skin from the patient infected with S. dimidiatum contained fungal cells that were labeled by melanin-binding MAbs, and digestion of the tissue yielded dark particles that were also reactive. S. hyalinum was also subjected to the melanin extraction protocol, but no dark particles were yielded.

Dose-time relationships for elicitation of contact allergy to para-phenylenediamine

Skin-sensitizing chemicals exhibit dose-response relationships for the elicitation of contact dermatitis. Previously, considerable work has been carried out in which the elicitation of allergic skin reaction has been examined as a function of the applied concentration. However, the relationship between exposure time, dose and response has not been explored in any depth. The present work has extended our initial assessment of the relationship between both exposure time and concentration for para-phenylenediamine (PPD) in a group of 19 PPD-allergic volunteers. The results clearly demonstrate that a relationship exists between both exposure time and concentration. Positive responses to PPD were directly proportional to exposure time: at 5 min 16% responded; at 15 min, 38%; at 30 min, 50%; and at 120 min, 69%. A similar direct relationship was found between concentration of PPD and response: after 120 min, 22% of patients had responded to 0.01%, and 69% to 1% PPD. All exposures for 1 and 2 min were negative. Subsequent evaluation using repeated 5 min open application testing demonstrated a cumulative effect, as after 8 days 39% of the panel reacted, more than double the number that reacted to a single occluded 5-min treatment. It was noted that there was marked subject variability in exposure time and dose required to elicit an allergic response. These results are of relevance for the general interpretation of patch test data, especially with regard to risk assessment.