Understanding Hormonal Therapies: Overview for the Dermatologist Focused on Hair

Skin, hair and beyond: the impact of menopause

The skin is an endocrine organ and a major target of hormones such as estrogens, androgens and cortisol. Besides vasomotor symptoms (VMS), skin and hair symptoms often receive less attention than other menopausal symptoms despite having a significant negative effect on quality of life. Skin and mucosal menopausal symptoms include dryness and pruritus, thinning and atrophy, wrinkles and sagging, poor wound healing and reduced vascularity, whereas skin premalignant and malignant lesions and skin aging signs are almost exclusively caused by environmental factors, especially solar radiation. Hair menopausal symptoms include reduced hair growth and density on the scalp (diffuse effluvium due to follicular rarefication and/or androgenetic alopecia of female pattern), altered hair quality and structure, and increased unwanted hair growth on facial areas. Hormone replacement therapy (HRT) is not indicated for skin and hair symptoms alone due to the risk-benefit balance, but wider potential benefits of HRT (beyond estrogen's effect on VMS, bone, breast, heart and blood vessels) to include skin, hair and mucosal benefits should be discussed with women so that they will be able to make the best possible informed decisions on how to prevent or manage their menopausal symptoms.

A Cell Membrane-Level Approach to Cicatricial Alopecia Management: Is Caveolin-1 a Viable Therapeutic Target in Frontal Fibrosing Alopecia?

Irreversible destruction of the hair follicle (HF) in primary cicatricial alopecia and its most common variant, frontal fibrosing alopecia (FFA), results from apoptosis and pathological epithelial-mesenchymal transition (EMT) of epithelial HF stem cells (eHFSCs), in conjunction with the collapse of bulge immune privilege (IP) and interferon-gamma-mediated chronic inflammation. The scaffolding protein caveolin-1 (Cav1) is a key component of specialized cell membrane microdomains (caveolae) that regulates multiple signaling events, and even though Cav1 is most prominently expressed in the bulge area of human scalp HFs, it has not been investigated in any cicatricial alopecia context. Interestingly, in mice, Cav1 is involved in the regulation of (1) key HF IP guardians (TGF-β and α-MSH signaling), (2) IP collapse inducers/markers (IFNγ, substance P and MICA), and (3) EMT. Therefore, we hypothesize that Cav1 may be an unrecognized, important player in the pathobiology of cicatricial alopecias, and particularly, in FFA, which is currently considered as the most common type of primary lymphocytic scarring alopecia in the world. We envision that localized therapeutic inhibition of Cav1 in management of FFA (by cholesterol depleting agents, i.e., cyclodextrins/statins), could inhibit and potentially reverse bulge IP collapse and pathological EMT. Moreover, manipulation of HF Cav1 expression/localization would not only be relevant for management of cicatricial alopecia, but FFA could also serve as a model disease for elucidating the role of Cav1 in other stem cell- and/or IP collapse-related pathologies.