What is the likely etiology for hypopigmented lesions worsening in summer on a child?

• A. Fungal infection
• B. Decreased active melanocytes
• C. Allergic reaction
• D. Vitamin deficiency

Answer: (B)

The presence of hypopigmented lesions in a child that worsen in the summer is most likely due to decreased active melanocytes. Melanocytes are the cells in the skin responsible for producing melanin, which gives skin its color. During the summer months, increased sun exposure typically stimulates melanocyte activity in normal skin, leading to tanning. However, if the melanocytes in a specific area are inactive or decreased, the affected skin will not tan appropriately, resulting in more pronounced hypopigmentation. This can occur in conditions like vitiligo or idiopathic hypomelanosis, where the skin loses its pigmentation and becomes more noticeable against tanned surrounding skin.

Fungal infections might cause changes in skin appearance, but they usually present differently and might not specifically worsen during summer. Allergic reactions typically result in rashes or skin irritation rather than hypopigmented lesions. Vitamin deficiencies can lead to various skin conditions, but they are less likely to cause disproportionate worsening of hypopigmentation due to sun exposure compared to issues directly related to melanocyte activity.