Psoriasiform skin reaction due to Brazilian keratin treatment: A clinical-dermatoscopic study of 43 patients.

Introduction: Hair straightening products like the Brazilian Keratin Treatment (BKT) contain high concentrations of formaldehyde, and its use is associated with adverse effects. In 2016, seven cases of eczema-like psoriasiform skin reaction secondary to BKT were described for the first time. We aim to investigate the clinical characteristics and dermatoscopic findings of patients with psoriasiform skin reactions due to BKT. Materials and
Methods: A cross-sectional study was performed from October 2017 to June 2020. Patients who developed erythema and scales on the scalp following the use of BKT were included. Age, sex, number of BKTs, time elapsed between BKT and the skin reaction, pull test, and dermatoscopic findings were investigated. Descriptive and inferential statistics were used.
Results: We found 43 patients with a mean age of 35 ± 10 years, predominantly females in 42 (98%) cases. The mean number of BKTs was 2 ± 2. The mean length of time elapsed to present the reaction was 12 ± 17 months and this was related to the number of BKTs (P = 0.01). The pull test was positive in 37 (86%) patients. The most frequent dermatoscopic findings were perifollicular scales in 42 (98%), red patches in 35 (81%), and peripilar desquamation resembling the outer skin of an onion bulb in 32 (74%).
Conclusion: Hair straightening products are widely used and the psoriasiform skin reaction that develops afterward might be underdiagnosed. It is important to investigate the background of BKT in conjunction with the clinical and dermatoscopic findings suggestive of this cutaneous reaction. Copyright:

INTRODUCTION

Chemical products for straightening hair are widely used in several parts of the world like the United States and Latin American countries. Formaldehyde is one of the main compounds of these products and it has been widely used in Brazil since 2003.[12] Therefore, in general, the technique to straighten hair is known as the Brazilian Keratin Treatment (BKT), subsequently commercialized in other countries under different brands and compositions.

Due to its toxicity, formaldehyde has been prohibited in different countries; however, it is still commercialized through new products that, while labeled “formaldehyde-free,” contain some of its derivatives such as methylene glycol, glyoxylic acid, formalin, methylene oxide, paraformaldehyde, formic aldehyde, methanol, oxymethane, or oxymethylene. These last are known as “formaldehyde releasers” since, when applying them to the hair and subjecting them to the heat of commercial hair straightening irons, they release high concentrations of this organic and colorless substance in the form of a gas that can cause adverse effects, both for those who apply it and for those who receive the treatment.[134567]

These adverse effects include eye irritation,[89] sore throat,[10] the association with the development of cancer demonstrated in animal models,[1112] and the presence of cutaneous reactions.[713141516] With regard to the latter, in 2016, Gavazzoni-Dias et al.[17] reported seven patients from Brazil who developed erythema and scurf on the scalp after BKT; an occurrence that was called an “eczema-like psoriasiform skin reaction.”

In Mexico, reports of this type of reaction were not found. Our aim, therefore, was to investigate the clinical characteristics and dermatoscopic findings of such occurrences.

MATERIALS AND METHODS

Study design

A cross-sectional study was performed during the period of October 2017 to June 2020, at the Hair Restoration Center, Dermika Laser Dermatology Center, a private center specializing in hair and skin disorders located in Guadalajara, Jalisco, Mexico.

Patient selection

Patients of any sex, 18 years of age or older with a history of BKT, were included. Subjects with previously diagnosed psoriasiform illnesses, like psoriasis or seborrheic dermatitis; those who had received, in conjunction with BKT, another type of cosmetic treatment for their scalp or hair; and subjects with treatments based in topical and/or systemic corticosteroids, were excluded.

Definition of the illness and measurements

The psoriasiform skin reaction was defined as the development of erythema and scales on the scalp that began following the use of BKT, in a previously asymptomatic subject.

Patients who met the definition and selection criteria were interviewed to determine sex, age, number of BKTs, and interval of time between BKT and the development of the skin reaction.

Under conditions of adequate artificial light, a physical examination was performed to complete the following evaluations:

Direct, complete examination of the hair and the whole scalp to corroborate the presence of a psoriasiform skin reaction

Photographs were taken of the entire scalp from three viewpoints at the levels of medial, frontal, and temporal lines. The images were captured with the camera from an Apple iPhone XS® (Apple Incorporated; Cupertino California; USA) in 12 megapixels

Pull test. Performed with no shampoo used for 1 day before the test, on three different areas of the scalp (medial, frontal, and temporal areas). The test was made by grabbing the base of 20–60 hairs between the thumb, index, and middle fingers, and then firmly pulling the hairs. It was considered positive if >10% of the hairs detached from the scalp[18]

Dermatoscopic evaluation. To perform this, the scalp was divided up into three viewpoints at the medial, frontal, and temporal levels. The dermatoscopic images were made with polarized light from a dermatoscope DL3N® from Dermlite (Dermlite Company; San Juan Capistrano, California, USA).

Ethical aspects

The present study was performed in agreement with the norms and ethical guidelines for medical research on human beings as established by the Declaration of Helsinki (Fortaleza, Brazil; 2013) and with prior verbal consent of the participants. In accordance with Good Clinical Practices guidelines, the confidentiality of the participants was protected: At no time were they ever identified by name, and their anonymity was protected with the use of an assigned code.

Statistical analysis

The data processing was performed with the statistical program IBM®SPSS Statistics version 20 for Windows (IBM Corp., Armonk, NY; USA). To determine if the variables had a normal distribution, the Kolmogorov–Smirnov test was used. Descriptive statistics were used to determine proportions and means as a measure of central tendency and standard deviation as a measure of dispersion. To analyze the qualitative variables, the Chi-square test or Fisher's exact test was used depending on the case. To analyze the quantitative variables, the Mann–Whitney U-test was used. A value of P < 0.05 was considered statistically significant.

RESULTS

During the study period, we found a total of 53 patients with a history of BKT of whom 43 (81%) met the selection criteria. Six subjects (11%) were excluded because they had a previous diagnosis of seborrheic dermatitis before BKT, three (6%) were excluded for not having scales and erythema on the scalp, and one (2%) was excluded for having received topical corticosteroid treatments.

Of the 43 patients with a psoriasiform skin reaction due to BKT, females predominated in 42 (98%) cases, and there was one male case (2%). The mean age was 35 ± 10 years (range: 19–62 years). The number of BKTs was mean 2 ± 2 (range of 1–10), and 23 (53%) cases received only one application of BKT. The time elapsed between BKT and onset of the skin reaction was a mean of 12 ± 17 months; a time lapse of <30 days was reported in 20 (47%) subjects and >30 days in 23 (53%). It was observed that with a higher number of BKTs, the time it took for the onset of the skin reaction was less (P = 0.01, Mann–Whitney U-test).

The pull test was positive in 37 (86%) patients and was not related to the number of BKTs (P = 0.66, Fisher's exact test) nor to the time elapsed for the onset of symptoms (P = 0.39, Fisher's exact test).

The three most frequent dermatoscopic findings were perifollicular scales in 42 (98%) patients, red patches in 35 (81%), and peripilar desquamation resembling the outer skin of an onion bulb in 32 (74%) [Table 1]. The dermatoscopic findings were not related to the number of BKTs (P = 0.57, Chi-square test) nor to the time elapsed between BKT and the onset of symptoms (P = 0.99, Chi-square). In Figures 1 and 2, the clinical aspects of the psoriasiform skin reaction due to BKT and their dermatoscopic findings are illustrated.

Table 1

Dermatoscopic findings observed in the Psoriasiform skin reaction due to Brazilian keratin treatment (n=43)

Dermatoscopic findings	n	%
Perifollicular scales	42	98
Red patches	35	81
Peripilar desquamation resembling the outer skin of an onion bulb	32	74
Interfollicular scales	29	67
Glomerular vessels	25	58
Arborizing vessels	24	56
Elongated vessels	23	53
Twisted red loops	14	33
Red dots and globules	13	30

Figure 1

Clinical and dermatoscopic findings of the psoriasiform skin reaction due to Brazilian Keratin Treatment. (a) Presence of erythema and scales in the retro-auricular region, (b) Red patches (c) Interfollicular scales, (d) Peripilar desquamation resembling the outer skin of an onion bulb, (e) Perifollicular scales (magnification ×10)

Figure 2

Dermatoscopic findings observed in the psoriasiform skin reaction due to Brazilian Keratin Treatment. (a) Red dots and globules, (b) Twisted red loops, (c) Glomerular vessels, (d) Arborizing vessels, (e) Elongated vessels (atypical), (f) Red patches

DISCUSSION

In the present study, the prevalence of the psoriasiform skin reaction due to BKT was 81%, with a total of 43 cases, which contrasts with the original description of the seven published in 2016.[17] This suggests that it is an underdiagnosed entity despite the fact that BKT is widely used, so if this background is intentionally questioned, more cases can be diagnosed.

As expected, since straightening hair is a cosmetic treatment, the female sex predominated in 98% of cases; similar to the original description where the seven patients reported were women. The mean age in our subjects was 35 years, while Gavazzoni-Dias et al.[17] reported a mean age of 26 years, which could have been due to the sample size.

Opposite to the Brazilian case series where the patients only received one BKT, in our study, patients applied a mean of two treatments, and one of the cases even applied ten BKTs. This finding is important, not only for the risk that patients are subjected to each time they receive BKT but also because we found that with a higher number of treatments, the time to present a psoriasiform skin reaction is reduced. Perhaps, the continuous exposure to formaldehyde produces an accumulated toxicity that facilitates the appearance of symptoms. Although we did not perform contact test, according to Gavazzoni-Dias et al.,[17] the psoriasiform reactions on the scalp due to formaldehyde suggests a phenomenon of reaction to medications and not only to eczemas originating from irritation or allergies, since none of their patients had a positive contact test to that substance.

In our study, the mean time elapsed between the application of the BKT and the presence of symptoms was 12 months. While 47% of the patients presented symptoms before 30 days, the remainder had symptoms that appeared later on. Therefore, we consider that the diagnosis of psoriasiform skin reaction due to BKT should be considered even when the symptomatology does not present acutely as mentioned in the original description.[17]

From the clinical standpoint, although all of the patients presented with erythema and scales on the scalp, the lesions were not always psoriasiform in appearance, with lamellar scales, as reported in the Brazilian patients,[17] but we also found lesions similar to seborrheic dermatitis with fine silvery-white scales. In addition, we performed a pull test, an indirect finding of Telogen effluvium, which was positive in 86% of our patients. Although that test was not related to the number of BKTs nor to the time elapsed between the treatment and onset of symptoms, its high prevalence allows us to suggest that when faced with a dermatitis of the scalp, whether it is psoriasiform or seborrheic dermatitis in appearance, in addition to Telogen effluvium, we should look into the patient's historic use of BKT.

We did not document the presence of exudate or pustules as in some of the Brazilian patients,[17] which support that this skin reaction due to BKT could present without eczema. Furthermore, we did not find an increase in the size of the lymph nodes or involvement of other areas of the head; findings which were observed in the Brazilian case series.[17] These differences could be due to genetic factors or idiosyncrasies associated to the susceptibility to formaldehyde and development of contact dermatitis.[19]

With regard to the dermatoscopic findings, the most frequent was perifollicular scales observed in 98% of cases. However, the finding that orients more toward a psoriasiform skin reaction due to BKT is the peripilar desquamation that resembles the outer skin of an onion bulb. This finding was present in 74% of our patients comparing to 29% of the Brazilian subjects[17] and has not been documented in any other skin disorder. The presence of the dermatoscopic findings could suggest that the primary target of the formaldehyde exposure is the pilosebaceous unit, thus making it interesting to conduct future molecular studies with immunohistochemistry to corroborate this fact.

Another dermatoscopic finding that can lead to the diagnosis of a psoriasiform skin reaction caused by BKT is the interfollicular scales which are not present in psoriasis or seborrheic dermatitis, the most important differential diagnoses. The rest of the dermoscopic findings are shared by these two entities [Table 2],[1720212223] therefore, the dermatologist should ask about the history of BKT and perform a detailed examination.

Table 2

Dermatoscopic findings of the psoriasiform skin reaction due to brazilian keratin treatment and its two most important differential diagnoses17,20-23

Dermatoscopic findings	Skin reaction due to BKT (%)*	Psoriasis (%)	Seborrheic dermatitis (%)
Perifollicular scales	57-98	38.7	57.1
Interfollicular scales	43-67	-	-
Red patches (unstructured areas)	81	64.5	46.4
Peripilar desquamation resembling the outer skin of an onion bulb	43-74	-	-
Glomerular vessels	58	22.4-65	22-43.8
Arborizing vessels	56	9-35.5	49-73.2
Elongated vessels (atypical)	53	29.2-67.7	47.3-71
Twisted red loops	33	37.3-61	19-22
Red dots and globules	14-30	42.9-87	6.3-22

*Percentages from the Brazilian case series17 and our series

Regarding the mechanism by which BKT, specifically the formaldehyde or formaldehyde releasers, produce these clinical and dermatoscopic manifestations remain unknown. Gavazzoni-Dias et al.[17] suggest that the tumor necrosis factor-alpha (TNF-α) has a role in its development because it is a cytokine with pleiotropic functions[24] that can lead to the clinical characteristics observed in our patients. That functions include (a) maturation of the Langerhans cells which would initiate the cutaneous reaction; (b) proliferation of the keratinocytes and increase in the expression of growth factors which would explain the presence of scales; and (c) increase the expression of adhesion molecules of the endothelial vasculature that could explain the presence of erythema and vascular dermatoscopic findings. In addition, it has been demonstrated that the presence of TNF-α gene polymorphisms augments the risk for the development of allergic contact dermatitis[1925] and that patients undergoing treatment with anti-TNF inhibitors can develop paradoxical psoriasiform reactions seemingly secondary to an overproduction of interferon alpha.[2627] Furthermore, Mabuchi et al.[28] demonstrated in murine models that the production of interleukin-23 (IL-23) through the TNFα, IL-20R2, and IL-22 pathway may have an important role in the development of acanthosis and hyperkeratosis,[293031] as showed in the biopsies of the patients described by Gavazzoni-Dias et al.[17] Nevertheless, given the scarcity of published cases of psoriasiform skin reactions due to BKT, more studies are required to identify the definitive role of TNF-α and other cytokines.

The main limitations of our study are that we did not perform patch tests or biopsies in our patients, and due to its transverse nature, we cannot tell if the alterations found are transitory or permanent.

Nevertheless, we can report new information that alerts about the presence of this diagnosis: (a) the fact that the psoriasiform skin reaction due to BKT can present without eczema, (b) it does not always present acutely after BKT, (c) it can appear similar to psoriasis as well as seborrheic dermatitis, and (d) it can be accompanied by Telogen effluvium in a high percentage of patients. In addition, we support the evidence that peripilar desquamation similar to the outer skin of an onion bulb is the most indicative finding of this entity.

CONCLUSION

It is important for health-care personnel, primarily dermatologists, to become familiar with psoriasiform skin reactions due to BKT; since straightening products are popular, easy to obtain, and have high concentrations of formaldehyde that exceed recommended levels.[7] In addition, patients must be alert of this too so they can avoid its use.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.