Skin and hair phenotypes are powerful cues in human communication. They impart much information, not least about our racial, ethnic, health, gender and age status. In the case of the latter parameter, we experience significant change in pigmentation in our journey from birth to puberty and through to young adulthood, middle age and beyond. The hair follicle pigmentary unit is perhaps one of our most visible, accessible and potent aging sensors, with marked dilution of pigment intensity occurring long before even subtle changes are seen in the epidermis. This dichotomy is of interest as both skin compartments contain melanocyte subpopulations of similar embryologic (i.e., neural crest) origin. Research groups are actively pursuing the study of the differential aging of melanocytes in the hair bulb versus the epidermis and in particular are examining whether this is in part linked to the stringent coupling of follicular melanocytes to the hair growth cycle. Whether some follicular melanocyte subpopulations are affected, like epidermal melanocytes, by UV irradiation is not yet clear. A particular target of research into hair graying or canities is the nature of the melanocyte stem compartment and whether this is depleted due to reactive oxygen species-associated damage, coupled with an impaired antioxidant status, and a failure of melanocyte stem cell renewal. Over the last few years, we and others have developed advanced in vitro models and assay systems for isolated hair follicle melanocytes and for intact anagen hair follicle organ culture which may provide research tools to elucidate the regulatory mechanisms of hair follicle pigmentation. Long term, it may be feasible to develop strategies to modulate some of these aging-associated changes in the hair follicle that impinge particularly on the melanocyte populations.

Photoaggravation of hair aging includes various chemical and physical changes in fiber properties which lead to an increase in fiber porosity, loss of mechanical strength and an increase in surface roughness. These changes come from lipid oxidation, disulfide bond cleavage, tryptophan degradation and cysteic acid formation. Hair exposed to sunlight is claimed to be more brittle, stiffer and drier than before irradiation and exhibits a reduced water-absorption capacity. Hair pigments function to provide photochemical protection to hair proteins. Hair pigments accomplish this protection by absorbing and filtering the impinging radiation and subsequently dissipating this energy as heat. However, in the process of protecting the hair proteins from light, the pigments are degraded or bleached. Dark hair is more resistant to photodegradation than light hair, because of the higher photostability of eumelanin compared to pheomelanin. Integral lipids of hair fibers are degraded by ultraviolet light, as well as by visible light, helping to explain the weakening of the cell membrane complex exposed to light radiation.

Hair infection by fungal agents, also called trichomycoses, is one of the common concerns in human beings. The common agents causing hair infections are dermatophytes, Malassezia species and those causing piedra. The former two can give rise to considerable discomfort and also cause immune-mediated reactions in the form of kerion and dermatophytids. The etiopathogenesis of trichomycoses, along with its clinical aspects and the management, are briefed here.

Various methods are available for evaluation (for diagnosis and/or quantification) of a patient presenting with hair loss. Hair evaluation methods are grouped into three main categories: Non-invasive methods (e.g., questionnaire, daily hair counts, standardized wash test, 60-s hair count, global photographs, dermoscopy, hair weight, contrasting felt examination, phototrichogram, TrichoScan and polarizing and surface electron microscopy), semi-invasive methods (e.g., trichogram and unit area trichogram) and invasive methods (e.g., scalp biopsy). Any single method is neither 'ideal' nor feasible. However, when interpreted with caution, these are valuable tools for patient diagnosis and monitoring. Daily hair counts, wash test, etc. are good methods for primary evaluation of the patient and to get an approximate assessment of the amount of shedding. Some methods like global photography form an important part of any hair clinic. Analytical methods like phototrichogram are usually possible only in the setting of a clinical trial. Many of these methods (like the scalp biopsy) require expertise for both processing and interpreting. We reviewed the available literature in detail in light of merits and demerits of each method. A plethora of newer methods is being introduced, which are relevant to the cosmetic industry/research. Such methods as well as metabolic/hormonal evaluation are not included in this review.

Background: Hamilton-Norwood scale (HNS) has been largely used to assess clinically the severity of androgenetic alopecia (AGA), especially for therapeutical trials and even to establish its association with important diseases such as ischemic heart disease and prostate cancer. Objective : To study HNS reproducibility in the hands of dermatologists and dermatology residents. Materials and Methods: Seven dermatologists and 16 residents in dermatology classified 43 photographs of male heads with different degrees of AGA. In a second study, 8 appraisers (3 dermatologists and 5 residents in dermatology) examined 56 pictures with the same procedure and repeated the observation 3 months later. In the first study, the inter-rater agreement was estimated by calculating an intra-class correlation coefficient (ICC). In the second study, for intra-rater repeatability, each rater's scores from session 1 were paired with his/her scores for the same subjects in session 2, and the ordinary least products linear regression was calculated. Results: In the first study, the concordance of appraisers was unsatisfactory (ICC = 0.63-0.68)]. In the second study, repeatability was poor, without any significant difference between dermatologists and dermatology residents. Comment: Reliability of HNS is unsatisfactory even in the hands of expert appraisers. To obtain better reliability, the number of classes should be reduced, but with such reduction HNS would be usable to classify patients only in a broad way.

Objective: Establishing the trichoscopy criteria of female androgenic alopecia (FAGA). Design: Trichoscopy images were retrospectively evaluated. Setting: Dermatologic hospital-based clinic and private practice offices. Patients and methods: One hundred and thirty-one females (59 with androgenic alopecia, 33 with chronic telogen effluvium (CTE), 39 healthy controls). The diagnosis was based on clinical examination and confirmed by histopatology. Main Outcome Measure: Trichoscopy results obtained in frontal, occipital and both temporal areas of the scalp under a 20-fold and 70-fold magnification, including average hair thickness, number of 'yellow dots' and vellus hairs, number of hairs in one pilosebaceous unit and percentage of follicular ostia with perifollicullar hyperpigmentation. Results: Average hair thickness in frontal area versus occiput was, respectively, 0.061 ± 0.008 mm versus 0.058 ± 0.007 mm in healthy controls, 0.047 ± 0.007 mm versus 0.052 ± 0.008 mm in androgenic alopecia and 0.056 ± 0.007 mm versus 0.053 ± 0.009 mm in CTE. Mean percentage of thin hairs (< 0.03 mm) in androgenic alopecia was 20.9 ± 12% and was significantly higher than in healthy controls (6.15 ± 4.6%, P < 0.001) or in CTE (10.4 ± 3.9%, P < 0.001). The number of yellow dots, pilosebaceous units with only one hair and with perifollicular hyperpigmentation was significantly increased in androgenic alopecia. Classification and Regression Tree Analysis was performed to establish diagnostic criteria for FAGA. Conclusion: FAGA may be differentiated from CTE based on trichoscopy criteria. Major criteria are ratio of (1) more than four yellow dots in four images (70-fold magnification) in the frontal area, (2) lower average hair thickness in the frontal area compared to the occiput and (3) more than 10% of thin hairs (below 0.03 mm) in the frontal area. Minor criteria encompass increased frontal to occipital ratio of (1) single-hair pilosebaceous units, (2) vellus hairs and (3) perifollicular discoloration. Fulfillment of two major criteria or one major and two minor criteria allows to diagnose FAGA based on trichoscopy with a 98% specificity.

Context: Male androgenetic alopecia (AGA) is a common condition. There is limited information on its prevalence and patterns. Aims: (1). To find the prevalence and most common pattern (2). To correlate the age and pattern of alopecia. Settings and Design: Population-based study. Materials and Methods: This is a population-based study from the public. The selection was random. The method involved was asking the age and, if found to between 30 and 50 years, the scalp was examined for alopecia and the pattern was determined using the Hamilton Norwood classification. Results: Of 1,005 subjects, the youngest was 30 years old and the oldest 49 years old, with a mean age of 37.05 6 standard deviation 4.79. 39.2% of the subjects were in the age group of 30-35, 34.4% in the 36-40 year age group, 26.0% in the 41-45 years age group and 0.4% in the 46-50 years age group. Five hundred and eighty-three subjects (58%) had AGA, the most common type being grade II (27.27%) followed by grade I (22.12%) and grade III (21.78%). 47.5% ( P = 0.003) had pattern alopecia in the 30-35 years age group, 58.7% in the 36-40 years age group ( P = 0.8) and 73.2% in the 41-45 years age group ( P ≤ 0.001). In the 30-35 years age group, grade I was 51.18%, grade II was 42.77% and grade VI was 18.52%. In the 41-45 years age group, grade I was 13.38%, grade III was 33.85% and grade VI was 66.67%. Conclusions: Fifty-eight percent of the male population aged 30-50 years had AGA. Its grade increased with increase in age. 12.9% of the male population had grades IV to VI, and would benefit from hair transplantation while 44.1% had grades I to III and are potential candidates for medical treatment

Background: Videodermoscopy (VD) is a noninvasive diagnostic tool that provides useful information for the differential diagnosis of scalp disorders. Objectives: The aim of this study was to investigate if dermoscopy may help the clinician in the diagnosis of contact dermatitis of the scalp. Materials and Methods: We analyzed the dermoscopic images taken from 7 patients with contact dermatitis due to topical minoxidil, 6 patients complaining of intense scalp itching during treatment with topical minoxidil but with negative patch tests and 19 controls. The following dermoscopic patterns described for scalp diseases were evaluated: Vascular patterns (simple loops, twisted loops and arborizing lines), follicular/perifollicular patterns (yellow dots, empty ostia, white dots, peripilar signs), white scales, yellow scales, follicular plugging, hair diameter diversity, honeycomb pattern and short regrowing hairs. Findings were graded from 0-4, according to severity in 20-fold magnifications. Statistical analysis included univariate analysis and Chi-square test by SPSS version 12. Results: There were no statistical differences in the analysis of the vascular patterns and scales between the 3 groups. Conclusions: We were not able to detect dermoscopic features that can help the clinician in distinguishing scalp contact dermatitis due to topical minoxidil from other conditions that cause severe scalp itching. In particular, minoxidil contact dermatitis does not produce increase or alterations in the morphology of the scalp vessels or significant scalp scaling when evaluated with dermoscopy.

Desmoglein 1 and 3 are distributed in the outer root sheath (ORS) of the hair follicle. Direct immunofluoresence (DIF) pattern of ORS in cases of pemphigus resembles the DIF pattern of the perilesional skin. We performed a DIF of the anagen and telogen hair ORS in a case of pemphigus and correlated it with the DIF findings of perilesional skin. Telogen hair ORS promises to be a useful tool in performing DIF for the purpose of diagnosis and follow-up in cases of pemphigus

White Piedra is a superficial fungal infection of the hair caused by Trichosporon asahii. It is also known as trichomycosis nodosa or trichomycosis nodularis. We report two cases of White Piedra in a mother and her daughter for the rarity of such occurrence.