Q. My three-year-old daughter has itchy spots on her hands and legs that look like mosquito bites. A doctor told me children sometimes have this problem, but it goes away after they're four or five. Does this sound right? - Nitin Bhatnagar
A. These marks are called PIH, which stands for post-inflammatory hyper-pigmentation. PIH is common among people with sensitive skin resulting from various skin disorders or scratches, burns and cuts. Rashes, pimples and cosmetic procedures can also lead to it.
It's important to treat the underlying cause - your daughter must avoid mosquito bites, since every new bite leaves another PIH mark.
She can avoid bites by wearing long-sleeved shirts and long pants, using natural repellents such as citronella oil and sleeping under a mosquito net.
The itchiness can be relieved with a mild topical steroid like 1-per-cent hydrocortisone cream, which both soothes the itch and has an anti-inflammatory effect.
In most cases, PIH fades on its own over time - anywhere from six months to a few years depending on the depth of the pigmentation. Daily use of a broad-spectrum sunscreen (SPF 15 or greater) is also essential, since sun exposure makes PIH persist.
A variety of over-the-counter whitening creams containing Vitamin A derivatives, Vitamin C, azelaic or glycolic acids or mulberry can be applied to help speed the healing.
As to the application, I suggest spreading the cream only on the affected area and being patient - it can take up to 12 months to see results. Stop using the cream if it irritates the skin.
If there's no significant improvement, consult a dermatologist for something more intensive, such as a prescription bleaching cream or cosmetic procedure.
- Thidakarn Ratanabanangkoon, MD, is an anti-ageing physician and dermatologist at Samitivej Srinakarin Hospital's Esthetics Institute.
