Sir,
Thyroid hormones along with estrogen, glucocorticoid, retinoids, prolactin, and growth hormone modulate hair growth.[1] Hyperthyroidism and hypothyroidism both are associated with hair shaft abnormalities.[2] Here, we report a case of an infant with congenital hypothyroidism who suffered diffuse hair loss due to levothyroxine overdose.
A 9-month-old female infant, born of non consanguineous marriage, presented to our hospital with partial neck holding and developmental delay. The infant weighed 6900 g (3rd-15th percentile) and was 67 cm long (3rd-15th percentile). Physical examination revealed lethargy, hoarseness, dry skin, depressed nasal bridge, and macroglossia [Figure 1a and b]. The results of the laboratory tests were suggestive of congenital hypothyroidism (Total T3-25 ng/dL, total T4-0.01 μg/dL, TSH >150 μIU/dL). Ultrasonography of neck revealed agenesis of thyroid gland. Infant was started on levothyroxine 50 μg/day (7.24 μg/kg/day). Fifteen to twenty days after starting levothyroxine, infant's mother noticed diffuse loss of scalp hairs. On examination, infant had non-scarring alopecia involving around 50-60% of the scalp area [Figure 1c–e]. At this stage, serum T3 and T4 levels were quite high and TSH was suppressed (Serum free T3 = 6.13 pg/ml, free T4 = 2.74, TSH = 0.039 μIU/dL). Levothyroxine overdose was suspected as the cause of effluvium hence dose was reduced to 37.5 μg/day. Follow up after 45 days showed marked regrowth of hair [Figure 1f and g] which was normal in texture and distribution while on levothyoxine maintenance dose. To conclude, levothyroxine overdose may lead to hair loss and should be watched for.
Figure 1.
Clinical picture showing reversible scalp hair loss. (a and b) At the time of diagnosis, before starting thyroxine supplements. (c-e) 30 days after starting levothyroxine (50 μg/day). (f and h) 45 days after reducing levothyroxine dose
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REFERENCES
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