Hair Morphology, Biogenesis, Heterogeneity, Pathophysiology and Hair Follicle Penetration
Heather A.E. Benson, Michael S. Roberts, Vânia Rodrigues Leite-Silva, Kenneth A. Walters in Cosmetic Formulation, 2019
Although not visible at first sight, the hair and the hair follicle provide multiple functions in humans. First, the hair is a sensory organ. The autonomous nervous system can induce the erection of the hair, which is controlled by the arrector pili muscle leading to so-called goosebumps which are mainly triggered by coldness, anxiety or emotions (Benedek and Kaernbach, 2011). Animals use this effect to appear larger and more threatening to their enemies; for men, this function seems to play a subordinate and sometimes even annoying role (Benedek and Kaernbach, 2011). Moreover, hairs provide several protective functions. Eyelashes and eyebrows, for example, can prevent sweat and foreign particles from reaching the eyes. Scalp hair offers efficient sun protection (Parisi et al., 2009) as can be seen in the high incidence of skin cancer on the scalp of bald men. Nowadays, scalp hair is a very important instrument of psychosocial communication. A loss of scalp hair frequently induces severe psychological strain (Katoulis et al., 2015).
Aesthetic
Tor Wo Chiu in Stone’s Plastic Surgery Facts, 2018
The normal eyebrow shape is as follows: The medial limit forms a ~vertical line joining the inner canthus with the lateral alar groove.The lateral limit forms an oblique line joining the outer canthus with the lateral alar groove.The lateral brow end lies slightly above the medial end. The medial brow is more club shaped, whilst the lateral brow tapers out to a sharper end.The highest part of the eyebrow lies directly above the outer limbus of the iris (junction of medial two-thirds and lateral one-third of the brow).
Eczema (dermatitis)
Ronald Marks, Richard Motley in Common Skin Diseases, 2019
Virtually any body site can be affected. The face is often involved (Fig. 10.7) as are the ankles, the backs of the knees (Fig. 10.8), the antecubital fossae and the wrists. The cheeks are often pale and this feature, taken together with crease lines just below the eyes (known as Denny Morgan folds) due to continual rubbing, makes the facial appearance quite characteristic (Fig. 10.9). In addition the eyebrows tend to be sparse. Running a blunt instrument (such as a key) over affected skin produces a white line in about 70 per cent of patients (Fig. 10.10) – known as ‘white dermatographism’. This is the reverse of the normal triple response and disappears when the condition improves. This paradoxical blanching is similar to that seen after intracutaneous injection of methacholine or carbamyl choline in atopic dermatitis patients.
Evaluation of the eyebrow position after aponeurosis advancement
Published in Journal of Plastic Surgery and Hand Surgery, 2019
Kenichi Kokubo, Nobutada Katori, Kengo Hayashi, Jun Sugawara, Seiko Kou, Akiko Fujii, Syou Kitamura, Ryunosuke Ninomiya, Jiro Maegawa
The MRD1 and the distance between the medial canthi were measured preoperatively. Both a frontal portrait and a close-up midface photograph were obtained preoperatively and at 3 months postoperatively. Care was taken to minimize image distortion and to ensure that patients were relaxed for the photographs. All photographs were scanned and projected on a computer screen using Adobe imaging software. The distance between the medial canthi and the eyebrow heights at the medial canthus, center of the pupil, and lateral canthus were measured (Figure 2). The eyebrow height was defined as the distance from a reference horizontal plane drawn between the medial canthi to a vertical point on the superior border of the eyebrow. The ratio of medial canthi distance measured on screen and the actual distance measured preoperatively, was used to calculate the actual eyebrow positions at the medial canthus, center of the pupil, and the lateral canthus. The change in eyebrow position was determined by calculating the difference between the postoperative and preoperative eyebrow position. A negative value of change indicated eyebrow elevation. The correlations between the change in eyebrow position and MRD1 were statistically analyzed.
Relationship between ocular dominance and brow position in patients with blepharoptosis
Published in Orbit, 2018
Andrew W. Thorne, Rao V Chundury, Julian D Perry, Daniel B Rootman
Despite these possibilities, physiologic mechanisms other than somatic or sensory input from eyelid height may contribute to brow position. Anatomically, the eyebrow-to-eyelid margin length14 and the central eyebrow height both increase with advancing age15 and may be related to the increasing incidence of eyelid ptosis over time.16–18 Perhaps changes in the eyebrow skin and soft tissue support systems or other neurologic factors result in these changes in eyebrow position. Further, the presence of brow ptosis in addition to blepharoptosis in our population may obscure our results, but at this time remains difficult to differentiate from blepharoptosis. Essentially, non-eyelid related factors could be driving this process in some way, leading to higher eyebrow positions in older individuals, the same individuals with a greater incidence of dermatochalasis and ptosis.16–19
Translational impact of omics studies in alopecia areata: recent advances and future perspectives
Published in Expert Review of Clinical Immunology, 2022
F. Buket Basmanav, Regina C. Betz
The molecular studies in AA which have yielded important insights into the pathogenesis of AA have provided support and contributed to the consideration of novel therapeutic modalities for AA. The outcomes of these trials were variable with some of them being unsatisfactory or contradictory and others being more promising. The finding that IL-23 subunits p40 and p19 were highly upregulated in AA scalp skin provided rationale for the repurposing of ustekinumab, an IL-12/IL-23p40 monoclonal antibody used for treatment of psoriasis and Crohn’s disease, for treatment of AA. Despite initial reports of some degree of success in pediatric and adult patients, lack of efficacy as well as development of AA coinciding with use of ustekinumab to treat other conditions was also reported [106]. Similarly, the results varied regarding the efficacy of PDE4 inhibition in AA patients treated by an oral PDE4 inhibitor, namely, apremilast, approved for the treatment of psoriasis, psoriatic arthritis, and Behçet’s disease [107]. In the recently published outcome of the open-label clinical trial of abatacept, the CTLA4-mimetic (NCT02018042), complete scalp hair re-growth was observed in one of the fourteen participants who completed the trial. In the other participants low (~3-10% hair re-growth, n = 4), intermediate (~15-25% hair re-growth, n = 4), or no response (n = 4) was noted and one patient showed regrowth of the eyebrows but not the scalp hair.
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