Female pattern hair loss is the most common hair loss disorder in women. Initial symptoms may develop during the teenage years [5].
FPHL is a complex polygenic disorder characterized clinically by diffuse hair thinning over the midfrontal scalp and increased hair shedding[6].
A number of agents have also been used in the treatment of female pattern hair loss including the androgen receptor antagonists spironolactone, cyproterone acetate, and flutamide as well as the 5 a reductase antagonist finasteride and dutasteride. These agents can be used either alone or in combination with topical minoxidil [7].
To the best of our knowledge this is the first study to compare the efficacy of topical sildenafil versus topical minoxidil in treatment of FPHL.
The results were in accordance with Lucky et al. (2004) who included a total of 381 women (18-49 years old) with female pattern hair loss applied 5% topical minoxidil solution (n = 153), 2% topical minoxidil solution (n = 154), or placebo (vehicle for 5% solution; n = 74) twice daily. The results of the study showed that after 48 weeks of treatment, the 5% topical minoxidil group demonstrated statistical superiority over the 2% topical minoxidil group and the placebo group in terms of increase terminal hair count, decrease vellus hair count and increase hair growth/scalp coverage[8].
Blume-Peytavi et al. conducted a study to compare the efficacy, safety, and acceptability and to show noninferiority of once-daily 5% minoxidil topical foam (MTF) with twice-daily 2% MTS in women with androgenetic alopecia. A total of 113 women with androgenetic alopecia were randomized to 24 weeks of treatment with 5% MTF or 2% MTS. The results showed that after 24 weeks, women randomized to 5% MTF once daily showed noninferior target area hair count and target area hair width and experienced greater, but nonsignificant, improvements in target area hair count, target area hair width, and overall efficacy by global photographic review than those randomized to 2% MTS used twice daily. 5% MTF was significantly superior to 2% MTS in participants' agreement with "the treatment does not interfere with styling my hair" (P = .002). Women randomized to 5% MTF experienced significantly lower rates of local intolerance (P = .046) especially in pruritus and dandruff compared with 2% MTS[9].
Choi and his colleagues investigated the expression of PDE5 in human dermal papilla cells (hDPCs) and human hair follicles (hHFs). The effects of sildenafil on hDPC proliferation were evaluated and the mRNA expression of growth factors and extracellular signal-regulated kinase (ERK) phosphorylation were investigated using real-time PCR and western blotting, respectively. Additionally, anagen induction and perifollicular vessel formation were evaluated using an in vivo mice model. The authors confirmed high expression of PDE5 in hDPCs and hHFs. Sildenafil enhances proliferation of hDPCs and up-regulates the mRNA expression of vascular endothelial growth factor (VEGF) and plateletderived growth factor (PDGF), which are responsible for hair growth. Additionally, sildenafil up-regulates the levels of phosphorylated ERK and accelerates anagen induction by stimulating perifollicular vessel formation after topical application in mice[4].
Stimulating blood flow in the human bald scalp promotes microcirculation in the surrounding HFs and can lead to promotion of hair growth and hypertrichosis. In addition, PDGF is also well known as a hair growth-promoting factor and is expressed in hDPCs and follicular keratinocytes[10].. Phosphodiesterase inhibitors helps to increase cutaneous blood flow and this helps in promoting hair growth.
As a support for this principal, Choi et al. (2018b) showed that cilostazol, a PDE3 inhibitor, promotes hair growth by stimulating hDPC proliferation, enhancing hair shaft elongation and acceleration of anagen induction in C57BL/6 mice[11].
The results of the current study agreed with a previous study by Al-Shabkhon et al. that was conducted in male patients with androgenic alopecia. The study included 30 male patients suffering from androgenic alopecia. Included patients were divided into 2 equal groups based on treatment received; one group received 1% topical sildenafil and the other group received 5% topical minoxidil. Assessment of treatment response was done using trichoscopy. The results showed that sildenafil treated group showed statistically significant increase in VH and TH count at 18 cm point, 24 cm point after treatment compared to before treatment. While, temporal side showed statistically significant increase in VH only. minoxidil treated group showed statistically significant increase in TH count, T/V hair ratio and hair thickness at 18 cm point and temporal side after treatment compared to before treatment. VH count was significantly decreased after treatment compared to before treatment at 18 cm point. At 24 cm point, only TH was significantly increased after treatment compared to before treatment[12].
The authors showed better treatment results in the minoxidil group and higher patients’ satisfaction. The degree of difference in treatment response was better noticed in the temporal region followed by the frontal region and at last the vertex[12].
Despite the reported efficacy of minoxidil, one of its major disadvantages is that the treatment needs to be continued indefinitely. If treatment is stopped, clinical regression occurs within six months. The degree of alopecia will return to the level that would have occurred if there were no treatment[7].
Female pattern hair loss is the most common hair loss disorder in women. Initial symptoms may develop during the teenage years [5].
FPHL is a complex polygenic disorder characterized clinically by diffuse hair thinning over the midfrontal scalp and increased hair shedding[6].
A number of agents have also been used in the treatment of female pattern hair loss including the androgen receptor antagonists spironolactone, cyproterone acetate, and flutamide as well as the 5 a reductase antagonist finasteride and dutasteride. These agents can be used either alone or in combination with topical minoxidil [7].
To the best of our knowledge this is the first study to compare the efficacy of topical sildenafil versus topical minoxidil in treatment of FPHL.
The results were in accordance with Lucky et al. (2004) who included a total of 381 women (18-49 years old) with female pattern hair loss applied 5% topical minoxidil solution (n = 153), 2% topical minoxidil solution (n = 154), or placebo (vehicle for 5% solution; n = 74) twice daily. The results of the study showed that after 48 weeks of treatment, the 5% topical minoxidil group demonstrated statistical superiority over the 2% topical minoxidil group and the placebo group in terms of increase terminal hair count, decrease vellus hair count and increase hair growth/scalp coverage[8].
Blume-Peytavi et al. conducted a study to compare the efficacy, safety, and acceptability and to show noninferiority of once-daily 5% minoxidil topical foam (MTF) with twice-daily 2% MTS in women with androgenetic alopecia. A total of 113 women with androgenetic alopecia were randomized to 24 weeks of treatment with 5% MTF or 2% MTS. The results showed that after 24 weeks, women randomized to 5% MTF once daily showed noninferior target area hair count and target area hair width and experienced greater, but nonsignificant, improvements in target area hair count, target area hair width, and overall efficacy by global photographic review than those randomized to 2% MTS used twice daily. 5% MTF was significantly superior to 2% MTS in participants' agreement with "the treatment does not interfere with styling my hair" (P = .002). Women randomized to 5% MTF experienced significantly lower rates of local intolerance (P = .046) especially in pruritus and dandruff compared with 2% MTS[9].
Choi and his colleagues investigated the expression of PDE5 in human dermal papilla cells (hDPCs) and human hair follicles (hHFs). The effects of sildenafil on hDPC proliferation were evaluated and the mRNA expression of growth factors and extracellular signal-regulated kinase (ERK) phosphorylation were investigated using real-time PCR and western blotting, respectively. Additionally, anagen induction and perifollicular vessel formation were evaluated using an in vivo mice model. The authors confirmed high expression of PDE5 in hDPCs and hHFs. Sildenafil enhances proliferation of hDPCs and up-regulates the mRNA expression of vascular endothelial growth factor (VEGF) and plateletderived growth factor (PDGF), which are responsible for hair growth. Additionally, sildenafil up-regulates the levels of phosphorylated ERK and accelerates anagen induction by stimulating perifollicular vessel formation after topical application in mice[4].
Stimulating blood flow in the human bald scalp promotes microcirculation in the surrounding HFs and can lead to promotion of hair growth and hypertrichosis. In addition, PDGF is also well known as a hair growth-promoting factor and is expressed in hDPCs and follicular keratinocytes[10].. Phosphodiesterase inhibitors helps to increase cutaneous blood flow and this helps in promoting hair growth.
As a support for this principal, Choi et al. (2018b) showed that cilostazol, a PDE3 inhibitor, promotes hair growth by stimulating hDPC proliferation, enhancing hair shaft elongation and acceleration of anagen induction in C57BL/6 mice[11].
The results of the current study agreed with a previous study by Al-Shabkhon et al. that was conducted in male patients with androgenic alopecia. The study included 30 male patients suffering from androgenic alopecia. Included patients were divided into 2 equal groups based on treatment received; one group received 1% topical sildenafil and the other group received 5% topical minoxidil. Assessment of treatment response was done using trichoscopy. The results showed that sildenafil treated group showed statistically significant increase in VH and TH count at 18 cm point, 24 cm point after treatment compared to before treatment. While, temporal side showed statistically significant increase in VH only. minoxidil treated group showed statistically significant increase in TH count, T/V hair ratio and hair thickness at 18 cm point and temporal side after treatment compared to before treatment. VH count was significantly decreased after treatment compared to before treatment at 18 cm point. At 24 cm point, only TH was significantly increased after treatment compared to before treatment[12].
The authors showed better treatment results in the minoxidil group and higher patients’ satisfaction. The degree of difference in treatment response was better noticed in the temporal region followed by the frontal region and at last the vertex[12].
Despite the reported efficacy of minoxidil, one of its major disadvantages is that the treatment needs to be continued indefinitely. If treatment is stopped, clinical regression occurs within six months. The degree of alopecia will return to the level that would have occurred if there were no treatment[7].