For many patients, complementary and alternative medicine (CAM) constitutes an important pillar in the management of dermatologic conditions. Traditional Chinese medicine, Ayurveda, and homeopathy all offer unique perspectives on the etiology and treatment of skin disease, and the safety and efficacy of these schools of CAM have been well described in the literature.1 A notable lacuna in the literature on CAM, however, is a consideration of Hispanic home remedies (remedios caseros) in the management of skin disease. With a burgeoning Hispanic community in the US, projected to reach almost 30 percent of the total population by 2060,2 it is likely that utilization of Hispanic home remedies will only expand. We present our findings of a focused review of five home remedies: chamomile, aloe vera (AV), green tea (GT), honey, and apple cider vinegar (ACV). We consider the efficacy of these remedies and also discuss potential adverse effects.
Chamomile (la manzanilla)
Chamomile, or la manzanilla, is a common home remedy utilized in the Hispanic community.3 In mouse studies, chamomile has been shown to have anti-pruritic effects,4 and chamomile extract has been demonstrated to possess bactericidal activity against Candida albicans and Staphylococcus aureus,5 two common culprits of skin infections. In vitro studies evaluating the potential of chamomile to manage skin cancer have also been promising. Components of chamomile have been shown to mitigate oxidative stress, a key contributor to the development of neoplasms.6 Additionally, chamomile has been demonstrated to exert an anti-proliferative effect on human melanoma SK-MEL-2 cells.7
The use of chamomile for the management of common dermatologic conditions, such as acne, atopic dermatitis (AD), and contact dermatitis (CD), has also been reported in literature. Chamomile has been shown to boost antimicrobial activity against Cutibacterium acnes, a major contributor to acne.8,9 Additionally, a cream containing chamomile extract has been shown to be superior to 0.5% hydrocortisone cream in achieving control of AD.10 CD also represents a potential target of chamomile therapy; chamomile was used in the management of paederus dermatitis in 15 patients from Venezuela.11 Moreover, chamomile has been suggested as a treatment for psoriasis, as chamazulene, an active ingredient in chamomile, inhibits leukotriene B4, an important instigator of psoriasis.12
There is a paucity of literature evaluating the potential of chamomile to treat other, less common dermatologic conditions. Nonetheless, topical chamomile treatment was reported to significantly improve the pain (p < 0.001), itching (p = 0.011), and burning sensation (p < 0.001) associated with oral lichen planus in a placebo-controlled randomized double-blind study.13 Additionally, chamomile may have the potential to treat a large repertoire of inflammatory skin conditions, as chamomile contains the flavonoid quercetin, which has been shown to dampen inflammation.12 The in vivo utility of chamomile in treating other inflammatory dermatologic diseases, however, remains to be elucidated.
Despite the broad range of applications of chamomile, adverse effects to chamomile treatments have been noted. CD and anaphylaxis have both been well-described complications of chamomile treatment.14 Nonetheless, the literature on adverse outcomes of chamomile treatment remains ambiguous. Lundh et al reported that chamomile did not provoke systemic allergic dermatitis in patients allergic to sesquiterpene lactones.15 There is a need for further studies evaluating chamomile treatment to obtain a realistic estimate of the true prevalence of adverse effects.
Aloe Vera (la sábila)
Aloe Vera (AV), or la sábila, is another mainstay of Hispanic home remedies. In a 90-patient study conducted in Amalia Simoni Argilagos Teaching Hospital in Cuba, AV cream showed remarkable efficacy in the management of acne, psoriasis, and dermatitis, resolving the lesions precipitating from these illnesses in 45.5 percent of patients and at least improving the lesions in 47.7 percent of patients.16 The utility of AV in targeting psoriasis in particular has been investigated. In a mouse tail model of psoriasis, AV gel boasted an anti-psoriatic activity of 81.95 percent (which was comparable to the 87.94 percent anti-psoriatic activity shown by the active control, tazarotene).17 A randomized clinical trial comparing topical AV treatment to 0.1 percent triamcinolone cream found that AV may actually be the superior treatment in ameliorating the lesions of psoriasis (p = 0237).18 A placebo-controlled study of AV in the treatment of psoriasis in 60 patients further supports the potential of AV in being an effective treatment for psoriasis, with AV demonstrating a 83.3 percent clearance rate (compared to 6.6 percent for placebo, p < 0.001).19
AV also shows promise against skin infections. In rats, AV cream has been shown to improve healing of skin wounds infected with MRSA compared to placebo (p < 0.01).20 And in a study of 30 patients with leg ulcers infected with multi-drug resistant bacteria, AV dressings reduced bacterial count in comparison to controls (p < 0.001); moreover, AV dressings eliminated bacterial count in 28 patients.21
A number of other dermatologic applications of AV have also been reported in literature. AV crude extract emulsion has been shown to be effective in the management of seborrheic dermatitis (compared to placebo, p = 0.009),22 and AV cream has been reported to decrease the number of rash sites seen in diaper dermatitis (compared to baseline, p < 0.001).23 AV has also been reported to result in better symptomatologic control of oral lichen planus compared to placebo (p < 0.001).24 The anti-inflammatory properties of AV are also intriguing. In fact, AV gel showed superior anti-inflammatory profile to 1% hydrocortisone.25 AV may also boast anti-aging properties: Cho et al showed that dietary AV supplementation decreased facial wrinkles (compared to baseline, p < 0.05) and posited that AV mediated downregulation of matrix metalloproteinase 1 to be a possible mechanism underpinning the anti-aging effects of AV.26
Finally, AV seems to boast a good safety profile, as there are few studies that describe adverse reactions to AV. Indeed, a patch testing study of 702 patients showed no reactions to AV.27 Nonetheless, cases of CD to AV have been reported: in a 51-year-old woman using 99% AV gel,28 in a 72-year-old woman with peripheral venous insufficiency who had been applying AV juice to alleviate her leg pain,29 and in another elderly patient.30 It is recommended to test with AV application on a small patch of skin first to test for allergy prior to expanding the area of application.31
Green Tea (el té verde)
Green Tea (GT), or el té verde, is yet another remedy in the remedios caseros toolbox. In particular, GT shows potential in controlling acne. Topical 2% GT lotion has been shown to result in a 58 percent reduction in acne lesions.32 Results of a randomized, double-blind placebo-controlled trial indicate a statistically significant reduction in facial acne lesions in patients treated with GT extract (p = 0.02).33 GT has also been reported to have bactericidal properties against C. acnes, Propionibacterium granulosum, S. aureus, and Staphylococcus epidermidis, all organisms that contribute to acne pathophysiology.34 Additionally, a Peruvian study showed GT extract boasts 47.96 percent inhibitory effect against C. acnes.35 Altogether, the anti-acne properties of GT are compelling.
GT also shows promise against a myriad of other skin conditions. In rat studies, application of GT extract hastened wound repair compared to Vaseline control (p = 0.018).36 In humans, GT extract bath therapy has been shown to effective in treating AD associated with Malassezia sympodalis.37 Also, in a patient with recalcitrant facial verruca who had exhausted all traditional treatments, GT ointment resulted in complete remission of all lesions within 20 days.38 Sinecatechin (an important polyphenol found in GT) has also been found to be superior to vehicle in the clearance of genital warts (p < 0.001).39
GT may also target two processes that underpin a host of dermatologic diseases: skin dysbiosis and oxidative stress. In mice, GT supplements were shown to alter the skin metabolome.40 Indeed, the skin microbiome (and the concomitant metabolome) has been implicated in a number of dermatologic diseases,41 and GT may represent one therapy for an aberrant skin microbiome. Additionally, GT consumption has been reported to increase the scavenging activity of skin compared to water (p < 0.05),42 and as free radicals have been implicated in cancer pathogenesis, GT may also represent a prevention strategy against cancer.
The topical use of GT seems to be relatively safe. GT has been shown to exert anti-inflammatory effects without inciting an allergic response.43 Oral consumption of GT extracts has also been reported to be generally safe, although case reports do suggest a link, albeit tenuous, between excessive concentrated GT extract consumption and hepatoxicity.44
Honey (la miel)
Honey, or la miel, has been touted as a highly effective remedio casero. The utility of honey in managing acne and psoriasis has been well described. A randomized controlled trial found that topical honey resulted in psoriasis control that was comparable to the control achieved by aqueous cream.45 Additionally, topical raw honey application led to the complete regression of palmoplantar psoriasis in a 68-year-old woman.46 Another case report showed a honey ointment to result in the complete regression of pustular psoriasis.47 The literature evaluating the efficacy of honey in managing acne is more mixed. Two Indonesian studies found honey to have bactericidal activity against C. acnes.48,49 However, a randomized clinical trial did not find honey in combination with antibacterial soap to be more efficacious in treating acne than the antibacterial soap alone (p = 0.17).50
Honey may benefit other dermatologic conditions, including rosacea, actinic keratosis, herpes simplex infections, and AD. A randomized controlled trial showed honey to be an effective treatment against rosacea compared to control at eight weeks (p < 0.001).51 In New Zealand, a 66-year-old man experienced complete, durable remission of actinic keratosis on his hand after applying honey over a three-month period.52 Furthermore, one study found topical honey treatment to be actually superior to acyclovir in the treatment of labial herpes simplex infections in eight patients, with statistically significant improvements (p < 0.05) in duration of attack, occurrence of crust, healing time, and pain duration. In eight other patients with genital herpes, honey was found superior (p < 0.05) to acyclovir in regard to duration of attacks and healing time. Additionally, while three patients treated with acyclovir developed itch, no patients treated with honey reported any side effects.53 In regard to AD, a 16-patient study showed that honey may represent a viable treatment for AD, as 14 of the 16 patients experienced an improvement in their AD lesions. The study also investigated the immunology underlying AD lesion improvement, and implicated the downregulation of IL4 induced CCL26 release to be a possible mechanism responsible for AD lesion regression.54 Thus, honey shows promise in management of dermatologic disease, yet additional studies are needed to corroborate the therapeutic efficacy of honey.
Many studies report the efficacy of honey in combination with other CAM therapies, though it is not possible to isolate the individual effect of honey in these remedies. A 1:1:1 mixture of honey, olive oil, and beeswax achieved mycological cure in75 percent of patients with pityriasis versicolor, 71 percent of patients with tinea cruris, and 62 percent of patients with tinea corporis.55 The same mixture also showed effectiveness against AD and psoriasis.56 Combination therapies incorporating honey are promising and warrant further study.
Honey appears to be a safe remedio casero. In a 46-person study with pollen allergy, no patient developed obvious anaphylaxis to honey syrup.57 Nonetheless, propolis, a resin-like material present in raw honey, has been reported to instigate systemic CD when ingested in a 36-year-old woman.58 CD in a beekeeper exposed to propolis59 and cheilitis due to propolis contained in homemade honey have also been reported.60 Propolis, then, appears to be the culprit in CD induction. Medicinal products using honey could benefit from propolis depletion.
Apple Cider Vinegar (el vinagre de manzana)
Apple Cider Vinegar (ACV), or el vinagre de manzana, is among the most popular remedios caseros. Yet despite its popularity, there is a paucity of literature evaluating the safety and efficacy of this home remedy. ACV has been indicated as a potential therapy for AD, as food-grade ACD shows bactericidal activity against Staphylococcus aureus.61 However, a clinical trial undermined the efficacy of ACV as a viable treatment for AD, as ACV was unable to strengthen the integrity of the skin barrier; rather, ACV caused irritation in 72.7 percent of subjects.62
A number of other adverse effects to ACV application have also been noted. A 14-year-old girl who applied ACV to remove nevi on her nose experienced subsequent irritation and erosions.63 A similar scenario was reported in a 11-year-old girl, who had also used ACV for removal of a nevus: although the nevus persisted, the ACV damaged her skin, with epidermal necrosis, neutrophil infiltration, and scar formation being observed on histologic examination.64 Burns from ACV used to treat mollusca contagiosa in an eight-year-old boy have also been reported.65 Altogether, ACV appears to be a remedio casero with a more concerning safety profile, and use of traditional therapies or other CAMs in lieu of ACV is recommended.
Conclusion
Chamomile, aloe vera, green tea, honey, and apple cider vinegar are all popular remedios caseros in the management of dermatologic disease. These remedies show promise against a variety of skin pathologies, and in some instances appear to be superior to the current paradigm of care. Nonetheless, adverse effects of these therapies have also been described, and their potential to cause deleterious side effects may be explain dermatologists’ reluctance to fully embrace remedios caseros.
We recommend that more research be done to further evaluate efficacy of home remedies and elucidate the epidemiological prevalence of adverse effects. Additionally, further study should be undertaken to identify the herbal remedies used in the Hispanic community, as much still remains to be uncovered. In fact, a 2018 study conducted in the Purépecha Plateau in Michoacán, Mexico, documented the use of eight plant species in the treatment of dermatologic disease whose use, at least dermatologically, had never before been reported.66 Furthermore, we should strive to gain a better understanding of the home remedies utilized by the Hispanic community in the US: a 2019 survey to analyze the CAMs used for psoriasis only had 6.2 percent Hispanic participants.67 Additionally, we should further investigate the potential synergy between CAMs and allopathic treatment. For instance, isotretinoin therapy, coupled with AV cream was shown to be superior in lesion control than isotretinoin therapy alone (p = 0.003) and also milder in its side effect profile.68 Another study found ketoconazole shampoo in combination with ACV to provide more rapid symptomatic relief than ketoconazole shampoo alone.69 Remedios caseros, then, comprise a group of CAMs that may be potent against certain dermatologic conditions. As the utilization of this group of CAMs may rise in the US in the coming decades, it is imperative to conduct further study to assemble a more comprehensive catalogue of the remedios caseros used and identify their adverse effects.
