Alopecia areata is an autoimmune condition that disrupts the immune privilege of hair follicles. The resulting hair loss is facilitated by the invasion of CD4+ and CD8+ T cells and the secretion of Th1 cytokines, which occur due to disruption of immune privilege in hair follicles (
6). The present study revealed a notable reduction in SALT score following a 3-month treatment with topical calcipotriol. This outcome aligns with the findings of Narang et al., Molinelli et al., and Abd-ElRaheem et al., who reported that calcipotriol usage led to expedited hair regrowth and a higher percentage of patches demonstrating a complete response (
9,
14,
15). In contrast, Cerman et al. observed that the effectiveness of topical calcipotriol in AA is weak, with an average of 27% total hair regrowth (
16). The obtained results can be attributed to the biological actions of vitamin D3 derivatives, which include regulation of proliferation and modulation of cytokine production (
17).
Similarly, Albalat and Ebrahim, Khan et al., and Balakrishnan et al. observed a swift enhancement following twelve weeks of intralesional PRP treatment (
18-
20). This result differs from Gupta et al., who indicated that PRP had limited effectiveness in treating chronic AA (
21). The disparity in outcomes may stem from the reduced number of PRP sessions in Gupta et al.’s research, which involved only three sessions, whereas our study administered six sessions over three months (
21).
The combination of topical calcipotriol and intralesional autologous PRP injections resulted in a notable reduction in SALT scores. This study demonstrated that group III (combined topical calcipotriol and PRP) saw significantly greater decreases compared to group II (PRP), followed by group I (topical calcipotriol).
This study found no significant variations in microscopic findings across the three groups of AA cases. The yellow dots indicator was prevalent in the three groups, with percentages of 69.2%, 76.2%, and 84.6%, respectively. Guttikonda et al. and Chiramel et al. revealed that the yellow dots sign was prevalent in their studies, with occurrences of 88% and 87.5%, respectively (
22,
23). Kibar et al. (
24) observed a low incidence of yellow dot symptoms. Inui et al. (
25) reported an occurrence of yellow dots at 73%; this discrepancy may be attributed to the yellowish skin tone prevalent among Asian cases, which may complicate the visual identification of yellow dots.
This study corroborated the findings of Chiramel et al. (
23) and Amer et al. (
26), who reported incidences of black dots at 79.5% and 75%, respectively. Conversely, Inui et al. (
25) and Bapu et al. (
27) observed that black dots were found in 45% and 36%, respectively. The exclamation mark was seen as a pathognomonic indicator in AA (
28). The present study revealed that the prevalence of the exclamation mark was 69.2% in group I, 61% in group II, and 84.6% in group III. These findings correspond with Rakowska et al. (
29), who stated a frequency of exclamation marks at 68% in their research. In contrast to research by Mane et al. (
30), which indicated a lower incidence of the exclamation mark sign at a rate of 12%. Black spots, tapering hairs, and broken hairs exhibited a positive correlation with disease activity. These findings elucidate discrepancies noted across several studies (
30).
In the present study, coudability hair was observed at an incidence of 61.5% in group I, 61.5% in group II, and 53.8% in group III. Rudnicka et al. (
31) corroborated our results, noting that coudability hair was detected in 42% of the patients. There are several limitations of this study, such as the lack of biomarkers and PRP quantification. Future multicenter studies should extend follow-up to at least 12 months to assess relapse and durability of remission.
5.1. Conclusions
This study concluded that topical calcipotriol, intralesional autologous PRP injection, and combined topical calcipotriol with intralesional autologous PRP injection were significantly effective in reducing SALT scores in patients with AA. This reduction was significantly more evident in the combined topical calcipotriol with intralesional autologous PRP injection group, followed by the intralesional autologous PRP injection group, and then the calcipotriol group. Future trials should include mechanistic biomarkers, long-term follow-up, and factorial or placebo controls.