Introduction
Melasma is one of the common acquired, chronic and relapsing hypermelanotic disorder, presenting clinically with bilaterally symmetrical brown-black circumscribed patches affecting mostly sun-exposed areas of skin, especially the face. It is most prevalent among young to middle aged women who are dark skinned and of Asian or African origin.1 Multiple factors have been proposed in its aetiopathogenesis like genetic factors, pregnancy, combined oral contraceptive pills(OCPs), exposure to sunlight, use of cosmetic preparations, thyroid gland dysfunction and drugs used for treatment of epilepsy.1, 2, 3, 4 Melasma affects men also, sharing the same clinical and histological features as in women, but hormonal factors do not seem to play an important significant role.5 The most striking concern with regards to melasma is the resultant cosmetic and social stigma, which drives an individual to seek a prompt therapeutic solution. Depending on the sites of involvement over face, melasma is classified into three types: centrofacial, malar and mandibular.2
Whether to screen all patients with melasma for thyroid disorders is a matter of discussion and yet to be proved. Till date many studies have been conducted to define the relationship between Melasma and thyroid autoimmunity. Many studies say, there is association between melasma and hypothyroidism, few studies showed no significant relation between melasma and thyroid autoimmunity. So, this study was performed to evaluate the association between thyroid autoimmunity and melasma in our tertiary care centre of north Karnataka.
Materials and Methods
Patients and controls
This study received ethical committee clearance at our institute, Raichur Institute Of medical Sciences in 2017. This was a prospective case control study. Patients who attended our dermatology outpatient department
Table 1
average serum levels of thyroid hormones in two groups
| Melasma group (n=50) | Control group (n=50) | P value | |
| Serum T3 (ng/ml) | 1.20±0.19 | 1.35±0.21 | P = 0.756 |
| Serum T4(µg/dl) | 8.56±1.59 | 8.36±1.97 | P= 0.93 |
| Serum TSH µIu/ml | 3.01±2.01 | 3.02±1.97 | P = 0.444 |
Table 2
Prevalence of thyroid dysfunction betweenmelasma and control groups
| Groups | Number of normal thyroid function | Number of hypothyroidism | Number of hyperthyroidism | P value |
| Melasma group (n= 50) | 45 | 5 | 0 | 0.712 |
| Control group (n=50) | 47 | 3 | 0 |
during the period march 2018 to august 2018 with the presenting complaints of melasma were enrolled in this study after taking informed consent in the local language. We enrolled 50 (fifty) patients(both males and females) in the age group between 20-50 years with melasma as cases and 50 age, sex matched individuals with no history of melasma as controls. Melasma was diagnosed by clinical examination using hand lens and if necessary by the help of Woods lamp examination.
Individuals who were excluded from the study were those (1)with pregnancy (2) known to have preexisting thyroid disease, (3) with coexistent any other autoimmune disorders or serious illness, (4) with history of drug intake that might interfere with thyroid function (steroids, lithium, amiodarone, iodide, heparin, beta blockers, anti-epileptics), (5) using pregnancy contraceptive medications and (6) patients on hormone replacement therapy.
We collected blood sample in sterile tubes with anticoagulant and sent to laboratory for the estimation of serum T3 (tri-iodo thyronine), T4 (thyroxine) and TSH (thyroid stimulating hormone) levels in all the cases and controls. A standardized questionnaire was used to obtain data.
Serum T3 and T4 were measured by radioimmuno assay method. Normal reference scale considered for T3 was 0.7-2.04 ng/ml and for T4 was 6.09-12.23 µg/dl. TSH was measured by immunoradiometric assay and the normal
reference range was 0.35-5.5µIu/ml. It was considered euthyroid if TSH, Serum T3 and T4 levels were within the normal limits. Hypothyroidism was considered when TSH was elevated above the normal limits and to confirm free T3 and free T4 was evaluated.
Results
50 cases with melasma and 50 controls without melasma were included in the study. The age distribution was between 20-50 years, female to male ratio was 7:1. Both the cases and controls were age and sex matched. The mean age group of the cases was 30.2 ± 3.4 years. The mean age group of the controls was 29.32 ± 5.6 years.
Average serum levels of the thyroid hormones (T3, T4 and TSH) in both the groups are shown in the Table 1. After calculating p value, we found that there was no significant difference in the mean levels of serum T3, T4 and TSH between the cases and the controls groups.
In melasma group out of 50 patients, 5 patients were found to be hypothyroid. Among 50 controls 3 individuals were found to be hypothyroid. There were no cases of hyperthyroidism.
There was no significant difference in the prevalence of thyroid disorders between the cases and the controls as the p value obtained was 0.712(p value >0.05) as shown in Table 2
Discussion
Thyroid dysfunction is the most common endocrine disorder associated with a wide range of manifestations. One of the organs that presents with a wide range of clinical signs and symptoms is the skin.6 The smooth functioning of the skin and hair depends on the general condition of the individual and it is controlled by circulating hormones such as the thyroid. Any major changes in thyroid gland function may present with skin manifestations such as change in color, texture, pigmentary disorders, hair fall, bullous lesions, photosensitivity etc.,
Many studies noticed various skin manifestations, especially melasma with thyroid disorders. In a study performed by Alka Dogra, pigmentary disorders were found in 37.5% of the patients with hypothyroidism.7 In a study conducted by Lutfi et al,8 thyroid disorders were 4 times more prevalent in patients than controls. In an another study performed by Kiani et al,9 also found thyroid disorders 3.4 times more prevalent in cases than controls.
Yazdanfar et al10 conducted a study in 2010; found that there is no significant difference between melasma cases and controls.
In our study mean serum TSH levels in melasma group was 3.01± 2.01 and in controls it was 3.02 ±1.97 µIu/ml which are almost same. We found no significant difference between cases and controls.
Conclusion
Few cases in our study were found to have hypothyroidism, but the mean levels of T3, T4 and TSH parameters showed no significant difference between cases and controls. This shows doubt in association of thyroid disorders and melasma. We suggest further studies with large sample size on melasma patients with coincidental thyroid disorders be performed.
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