D. Van Neste

Finasteride increases anagen hair in men with androgenetic alopecia

Background The growth of scalp hair is a cyclical process of successive phases of growth (anagen) and rest (telogen). In previous clinical trials in men with androgenetic alopecia, treatment with finasteride increased scalp hair counts in a defined area (i.e. increased hair density). Objectives The current study used a phototrichogram methodology to assess the effect of finasteride on the phases of the hair growth cycle. Patients/Methods Two hundred and twelve men, age 18–40 years, with androgenetic alopecia were randomized to receive finasteride 1 mg daily or placebo for 48 weeks. At baseline and at 24 and 48 weeks, macrophotographs were taken to measure total and anagen hair count in a 1‐cm2 target area of the scalp. Results At baseline, mean total and anagen hair counts in the finasteride group were 200 and 124 hairs, respectively (% anagen = 62%) and the anagen to telogen ratio was 1·74 (geometric mean). In the placebo group, the respective values were 196 and 119 hairs (% anagen = 60%) and 1·57. At week 48, the finasteride group had a net improvement (mean ± SE) compared with placebo in total and anagen hair counts of 17·3 ± 2·5 hairs (8·3% ± 1·4%) and 27·0 ± 2·9 hairs (26% ± 3·1%), respectively (P < 0·001). Furthermore, treatment with finasteride resulted in a net improvement in the anagen to telogen ratio of 47% (P < 0·001). In this study, treatment with finasteride 1 mg day−1 for 48 weeks increased both total and anagen hair counts, and improved the anagen to telogen ratio. Conclusions These data provide direct evidence that finasteride 1 mg daily promotes the conversion of hairs into the anagen phase. These data support that finasteride treatment results in favourable effects on hair quality that contribute to the visible improvements in hair growth observed in treated patients.

Comparative study of normal and rough human skin hydration in vivo: Evaluation with four different instruments

Abstract Appropriate monitoring of skin hydration during clinical and/or experimental trials needs devices with acceptable reproducibility and sensitivity under conditions ranging from increased, and normal to low hydration. The aim of this study was to compare the variation of electrometric data generated by 4 different instruments (Skicon Hygrometer, 2 CM420 and a CM820 corneometer) in normal and experimentally damaged skin displaying surface roughness. Rough skin sites were observed during the healing process after repeated tape stripping of stratum corneum in humans (e.g. 10–14 days after insult). They displayed lower conductance and/or capacitance levels as compared to normal skin sites of the same subjects. The Skicon hygrometer showed higher variability as compared to the corneometers and was less sensitive, in relative terms, in the rough skin sites. This device also showed a moderate zero drift and re-zeroing was repeatedly utilized during the experiment. When the corneometer data were plotted against the hygrometer data, the slope of the regression line generated by the CM420a was different from CM420b and from CM820; the two latter were not significantly different from each other. Hence, comparison of absolute data obtained under comparable conditions (in this case CM420a and CM420b) in a single laboratory should not be made without prior calibration. Standards for evaluating interinstrumental variation are currently unavailable. This aspect of the measurement of electrical properties of the skin has not been investigated in great detail and has often been neglected in the past. Our findings also indicate that a constant control over the performances of a particular device should further improve the reliability of the data.

Skin signs in the diagnosis of thallium poisoning

A 45‐year‐old man developed a painful and rapidly progressive sensory‐motor polyneuropathy associated with confusion and convulsions. This resulted in hypoventilation and led to respiratory failure and coma. A rapid and diffuse alopecia occurred after 3 weeks in the intensive care unit. Examination of hair roots under polarized light detected dystrophic anagen hairs with dark bands caused by empty spaces in the disorganized cortex. These dark zones were originally reported in patients with thallium poisoning and a toxicological investigation confirmed thallium exposure. The classical systemic symptoms and the various dermatological signs are reviewed, and the origins of contamination and physiopathology discussed.

Phototrichogram analysis: technical aspects and problems in relation to automated quantitative evaluation of hair growth by computer-assisted image analysis

Non-invasive methods are particularly suited for evaluation of the dynamics of hair growth and/or hair growth arrest. In particular, the duration of the growth phase of each individual follicle cannot be repeatedly estimated by invasive methods, i.e. skin biopsies which give an ‘irreversible snapshot’ of a dynamic process.

Agonist-antagonist interactions in the skin : comparison of effects of loratadine and cetirizine on skin vascular responses to prick tests with histamine and substance P

The skin vascular responses (weal, flare, blood flow measurements) elicited by intradermal administration by pricking of histamine (HS) and substance P (SP) were evaluated 6 h after a single intake of anti-H1 agents displaying different activity profile on skin tests at currently recommended dosages (loratadine 10 mg, cetirizine 10 mg) as compared to placebo (P). The weal and flare response and the increases of blood flow occurring in the usual flare area after HS and SP were almost completely abolished by cetirizine. Inhibition of HS- and SP-induced weal and flare reactions was less marked after loratadine and blood flow in the expanding flare after HS and SP showed significant fluctuations over time. In view of the present results and of data obtained in previous experiments with intradermal injection of agonists, we hypothesize that mode of administration of agonists significantly influences the size of the residual weal after anti-H1 agents. We demonstrate that SP weals induced by pricking are largely inhibited by a potent H1 blockade which supports the view that this phenomenon, as well as the SP-flare, is due to SP-induced histamine liberation. We also, for the first time, report on fluctuations recorded at the edge of the developing flare with laser Doppler flowmetry early after prick testing with a weak H1 blockade. This opens up new avenues in dynamically testing H1-receptor occupancy in vivo and in situ in human skin.

A controlled study of the effects of RU58841, a non‐steroidal antiandrogen, on human hair production by balding scalp grafts maintained on testosterone‐conditioned nude mice

Summary Human hair growth can be monitored for several months after the transplantation of scalp samples from men with androgen‐dependent alopecia on to female nude mice. Hair production from balding sites has been shown to be inhibited in testosterone‐conditioned nude mice. We used this recently reported model to study the effect of a new non‐steroidal antiandrogen – RU 58841 – on human hair growth. Twenty productive scalp grafts from balding men were maintained for 8 months after grafting on to nude mice, and hair production was monitored monthly for 6 months. All mice were conditioned by the topical application of testosterone (testosterone propionate. 300 μg in 10μL; 5 days/week) on the non‐grafted flank. The scalp samples were divided equally according to the estimated hair production potential, which was based on the amount of hair present on the scalp samples before grafting. Each of the two equal groups of grafts was further allocated at random to be treated topically (5 days/week) with blinded solutions of either RU 58841 1% in ethanol, or ethanol as a control.

Novel mutation in the human hairless gene once more erroneously diagnosed and treated as ‘alopecia areata’

Congenital atrichia or alopecia universalis congenita (MIM 209500 and MIM 203655) is a rare condition with an autosomal recessive mode of inheritance caused by mutations in the hairless (HR) gene. The human HR gene maps to the 8p12 locus and its mouse equivalent, chromosome 14, harbours the murine hairless locus. Affected individuals display normal hair growth at birth that is then lost during the first weeks or months of life. Hairs are typically absent on scalp, axilla and body while remains of sparse eyelashes and eyebrows may still be observed. Affected individuals may exhibit cutaneous papules appearing progressively during childhood. In that case, the disease is designated as atrichia with papular lesions (APL). Both men and women are equally affected and no abnormalities involving either the cutaneous or extracutaneous systems are found. Histopathological examination of the scalp or body hair reveals follicular cysts filled with keratinized material in concentric layers. Yet, despite its unique clinical picture and the pathognomonic association between universal alopecia and papular skin lesions, APL remains frequently misdiagnosed as the autoimmune disorder alopecia universalis (AU) and the papules mistakenly considered as keratosis pilaris or milia lesions. As a consequence, misdiagnosed patients are often treated for years with unnecessary topical or systemic immunomodulators and ⁄or psychological consultations. Nevertheless, disease burdens resulting from the inappropriate therapies could be easily avoided if clinical symptoms are clearly outlined. Zlotogorski et al. recently summarized the major findings in APL in an attempt to facilitate the earlier establishment of the diagnosis and to avoid the battery of pointless treatments.

Skin response to histamine dry skin prick test: Influence of duration of the skin prick on clinical parameters and on skin blood flow monitoring

This comparative trial (histamine dry skin prick test versus control prick test) evaluates with subjective and objective clinical methods (i.e. itch scores, wheal area, and wheal and flare area) and with laser Doppler flowmetry (multiple sites measured between 5 and 15 min after prick test) the effect of increasing the duration of the skin prick (1, 3 and 10 s). As compared with control prick tests, all objective clinical parameters after histamine prick test were significantly different from the control prick tests. There was no interaction between agonist-duration of prick test and clinical parameters. When present, itch was reported only after histamine prick test. Skin blood perfusion values were evaluated with Laser Doppler flowmetry at prick test sites and at 1 cm distance from the prick test site. At control and histamine prick test sites, increased blood flow values were observed and a moderate interaction between agonist-duration of prick test and repeated measurement was noted (one tail P < 0.05); there were indeed lower values 9 min after histamine prick tests whatever the duration of the prick test. At 1 cm distance from histamine prick test sites, all skin perfusion measurements (either 5–8 or 11–14 min) showed increased values over data recorded after control prick test (P < 0.0001). On pooled data recorded at distance from histamine or control prick tests, there was a significant interaction between agonist-duration of prick test and laser Doppler flowmetry (P < 0.0004). Indeed, only moderate changes were recorded at distance from the control prick test, with the exception of the reaction induced by the 10 s control prick duration, where highly significant increases of blood flow were recorded 11–14 min after testing. This reflects activation of the axon reflex mediated vasodilation only after prolonged duration of the control prick. Laser Doppler flowmetry appears to be a reliable and highly sensitive method for objective quantitative measure of skin blood perfusion at sites of and at distance from histamine injection with the dry skin prick test; short duration (i.e. 1 s) is recommended in order to record specific histamine related signals in a repeatable way.

Histamine-induced skin reactions using iontophoresis and H1-blockade

When skin wheals develop after intradermal (ID) injection of histamine, it is not possible to obtain their complete inhibition by previous H 1 blockade. Usually, the wheal areas can be markedly reduced by previous administration of a potent H 1 blocker (up to 80-85%), but residual wheals are present. If the prick technique is used for histamine skin challenge, a 100% inhibition of wheal development is more frequently observed even when very high histamine concentrations are used. This means that the prick technique, which is less traumatic, leads to the formation of a more specific H I-dependent wheal. We recently hypothesized that iontophoresis might be even a less traumatic method for histamine administration [1, 2]. In the present study, carried out on 10 healthy subjects, we investigated the H ]-dependency of a skin wheal induced by histamine introduced in the skin by iontophoresis.