Audit of Finn Chamber patch test preparation.

Reproducibility of patch test reactions is an important aspect of patch testing. Thin layer rapid use epicutaneous tests (TRUE Test) are preloaded with allergen, whereas Finn Chambers are empty discs that have allergen applied from a syringe. The amount of allergen applied to each Finn Chamber is therefore potentially variable depending on technique. This may increase the risk of non-reproducibility of reactions. We have performed an audit of patch test preparation in our department looking at weight variation of both individual Finn Chambers and 3 completed panels before and after allergen application. We found that the variance in weight was not significant for 2 of the 3 panels and single Finn Chambers with allergen in petrolatum. The variance in weight was significant for single Finn Chambers with allergen in solution and the third panel, which contains an allergen in solution. The clinical significance of these results is unclear.

Assessment of ropivacaine as a local anesthetic for skin infiltration in skin surgery.

BACKGROUND: There has been limited examination of the use of ropivacaine, a relatively new amide local anesthetic, for skin surgery following local infiltration. Initial studies of ropivacaine show it to have a rapid onset and long duration of action. OBJECTIVE: To establish the injection characteristics of different concentrations of ropivacaine and to compare the pain of infiltration of ropivacaine with lidocaine 2% + epinephrine 1:80,000. METHOD: A double-blind placebo-controlled study was carried out on 18 healthy volunteers. Four concentrations of ropivacaine (1, 2, 5, and 7.5 mg/ml) were injected intradermally. Normal saline was used as the control. Sensation for pinprick was used to assess the onset and duration of anaesthesia. Pain of infiltration of ropivacaine and saline was additionally compared with lidocaine 2% + epinephrine 1:80,000. RESULTS: Pain of ropivacaine infiltation increased with increasing strength, but only 5 mg/ml was significantly more painful than the control P =.002). Lidocaine and epinephrine infiltration was significantly more painful than the control P =.0002) and 7.5 mg/ml ropivacaine (P =.0005). Mean times to reach full anesthesia were 74 seconds for 5 mg/ml and 51 seconds for 7.5 mg/ml. Mean times to regain full sensation were estimated as 692 minutes for 5 mg/ml and 773 minutes for 7.5 mg/ml. A vasoconstrictor effect was noted in the ropivacaine sites. CONCLUSION: Ropivacaine has a rapid onset and long duration of action. Ropivacaine produces vasoconstriction which may be clinically relevant. Even at maximum strength ropivacaine is less painful to inject than lidocaine with epinephrine.

Yellow nail syndrome: the nail that grows half as fast grows twice as thick.

We report a case of a 51-year-old man with yellow nail syndrome (YNS).1 During a 23-week period of study, the dynamics of thumbnail growth were compared between one affected thumb and the normal contralateral thumb. Longitudinal nail growth was normal (0.46 mm/week) in the normal thumb and double that of the affected thumb (0.23 mm/week). Thickness of nail at the free edge in the affected thumb (0.97 mm) was twice that of the normal thumb (0.57 mm). Within the nail plate in the dorso-ventral axis there were 50% more cells in the affected thumb (358) in comparison with the contralateral control (242). This case illustrates that rate of longitudinal growth does not necessarily reflect nail plate production.

Pili annulati coincident with alopecia areata.

Pili annulati is a rare hair shaft abnormality of unknown pathogenesis which gives a gross beading effect. An association with alopecia areata has been reported. We present a 13-year-old girl who had alopecia areata and coincidentally was found to have pili annulati. Her mother also had pili annulati which had become more noticeable as her hair had become paler with age. We discuss the possible pathogenesis of pili annulati and relate that to the microscopic banding appearance of the hair shaft. We note the relevance of the condition becoming more apparent with age. We also discuss the probable coincidental association with alopecia areata.