Does zinc have a role in alopecia areata? A clinic-biochemical study

INTRODUCTION

Alopecia areata is a common recurrent non-cicatricial hair loss which can occur at any hair bearing area. The etiology is often multifactorial (immunological, hereditary, environmental, infection, and endocrine disorders), but the exact etiopathogenesis is not fully understood. Some studies suggest the possible role of trace elements in the pathogenesis of alopecia areata, mainly zinc.^[1] Oral zinc is often used in the treatment of hair disorders like telogen effluvium and alopecia areata even in the absence of zinc deficiency because of its hair growth modulatory properties. In recent studies, around 62% of patients with alopecia areata responded to oral zinc sulfate in a dose of 5 mg/kg/day in three divided doses for a period of 6 months. Furthermore, zinc supplementation could be given as an adjuvant therapy for patients with alopecia areata with a low serum zinc level and for whom the traditional therapeutic methods have been unsuccessful.^[2] This study is aimed at finding the correlation between the severity of alopecia areata and serum zinc levels.

MATERIALS AND METHODS

It is a hospital-based and cross-sectional study. All new patients with Alopecia areata attending dermatology clinic on outpatient basis in Sri Manakula Vinayagar Medical College and Hospital from November 2015 to May 2017 were included in the study after getting informed consent. We excluded patients who were already on treatment for alopecia areata, alcoholics, febrile patients, pregnant women, children <5 years, and those who had chronic gastrointestinal and renal disease.

The severity of alopecia areata was graded based on “Severity of Alopecia Tool score” (SALT score) Price and Gummer, 1989 and serum zinc levels were measured by calorimetric method. The demographic details and the clinical features were recorded in the predesigned proforma. Hair pull test and dermoscopy were done to confirm the diagnosis. Chi-square test was used to find the association between serum zinc levels and severity of alopecia areata.

RESULTS

A total of 88 alopecia areata cases who met the criteria were included in the study. The age of the patients ranged from 17 to 62 years (mean age 33.45 ± 10.50 years). Majority (70%) of the patients were between 20 and 40 years of age. A male preponderance was noted among the population with a ratio of 2:1. On analysis of occupation, majority were manual laborer (27%). Around 89.77% of the study population were non-vegetarians.

The duration of alopecia ranged from as early as 1 day–1 year. Most of the patients reported within 1 week duration and in around 76% of cases, the duration was <2 months. The lesions were progressive in around 58% of patients.

Number of patches ranged from 1 to 9. Around 77.27% of patients had only one patch. The size of the patch was <3 cm in 61% of cases. Hair pull test was positive in around 60% of population.

Patchy type of alopecia areata was the most common pattern encountered which constituted around 91%. The other patterns seen were diffuse, ophiasis, linear type, and alopecia universalis [Table 1].

The most commonly affected sites were occipital, parietal, and beard region. In around 25 cases, alopecia was noted in the non-scalp regions.

Scoring

SALT score

SALT scoring was used to evaluate alopecia involving the scalp regions of the body. Based on SALT scoring, 57 had mild and five had moderate severity of alopecia areata. None of them had severe alopecia areata.

Out of 62 patients, 46.77% of patients had mild and 4.84% had moderate alopecia areata.

Gauging score

Gauging score was used for both scalp and non-scalp areas. Based on this scoring, the number of mild, moderate, and severe cases was 57, 30, and 1, respectively.

Chi-square test did not show any significant association between serum zinc levels and alopecia areata based on SALT score and Gauging score [Tables 2 and 3]. No correlation was found between the severity of alopecia areata and serum zinc levels. The scatter plot showed no correlation between the two [Figures 1 and 2].

Table 2: Association between serum zinc levels and alopecia areata based on SALT score.

Based on SALT score
Serum zinc levels	Mild	Moderate	Total
<70	29	3	32
70–180	24	1	25
>180	4	1	5
Total	57	5	62
Chi-square	Probability
4.2334	0.3753

SALT score: Severity of alopecia tool score

Table 3: Association between serum zinc levels and alopecia areata based on Gauging score.

Based on Gauging score
Serum zinc levels	Mild	Moderate	Severe	Total
<70	33	12	1	46
70–180	22	15	0	37
>180	2	3	0	5
Total	57	30	1	88
Chi-square	Probability
4.1931	0.3805

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Figure 1:

Scatter plot showing no correlation between mild alopecia areata and serum zinc levels.

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Figure 2:

Scatter plot showing no correlation between moderate alopecia areata and serum zinc levels.

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DISCUSSION

Zinc is an essential micronutrients and is the second most abundantly distributed trace element in the body next to iron.^[3] Tissues with high cellular turnover such as skin and hair are characteristically affected by zinc deficiency.^[4] Although there have been no large scale studies on the prevalence of zinc deficiency in India, the available evidence suggests that zinc deficiency in uncommon in Indian population. Based on the WHO’s RDA, the risk of zinc inadequacy is only marginal among Indian population mainly because of the Indian style of cooking. The serum zinc levels are influenced by the age, diet, and health status. Zinc deficiency is more common with vegetarian diet, as the phytates in the vegetarian diet reduces the intestinal absorption of zinc.^[5]

Zinc deficiency is associated with various dermatological disorders. Oral zinc is often used in the treatment of hair disorders like telogen effluvium and alopecia areata even in the absence of zinc deficiency because of its hair growth modulatory property.^[2]

In our study, the most common age group affected was 20–40 years (70%) which was in concurrence with the study done by Tan et al. and Bhat et al.^[6,7] The mean age of onset has been reported as between 25.2 and 36.3 years in various studies done in other parts of the world.^[8] Similar to our study, the scalp was found to be the most common site involved, with or without involvement of other body sites.^[6,9]

Around 26.2% of patients had occipital involvement which was in concordance with another study where the occipital involvement was 38.4% for males and 33.4% for females.^[10] Majority of the patients had a single patch which was similar to the observations made by Fattah et al. and Bhat et al. in their studies.^[7,9] Majority of our patients were non-vegetarians and the levels of zinc did not correlate with diet.

Although majority of the patients had reduced serum zinc levels, there was no statistically significant difference in the occurrence of alopecia areata in those with zinc deficiency and those without. This was in concordance with the study done by Mussalo-Rauhamaa et al. where they found no difference in zinc levels in patients with alopecia areata when compared to normal controls.^[11,12] Further Fattah et al. in his study observed an inverse correlation between serum zinc levels and duration and severity of alopecia areata.^[11]

Studies done by Kil et al, Dastgheib L and El-Ashmawy showed that serum zinc deficiency was statistically more in patients with alopecia areata.^[13-15] The results of these studies on zinc in alopecia areata are summarized in [Table 4].

The main limitation of this study was that it was not a case controlled study and the patients were not followed up.

CONCLUSION

Zinc is an important nutrient required for hair growth as evidenced by various studies. The role of zinc in alopecia areata is not significant and probably other factors such as immunity and genetics have an important role to play. However in studies which showed improvement in alopecia areata after intake of zinc, the zinc was probably acting as a nutrient supplement rather than its role in pathogenesis.