Brief Answer:
Post inflammatory Hypo-pigmentation

Detailed Answer:
Hello,

Welcome and thanks for posting your query to the forum.

I can understand your concern for the white patches over the back of thigh area in your daughter. It is really distressing for every parent to get such kind of unusual appearance in our children.

I have gone through your complete query and also analyzed the pictures sent by you. After the analysis let me reassure you that your daughter has completely normal and usual appearance and there is nothing abnormal in it. It is also neither related Pityriasis XXXXXXX nor to vitiligo.

It is known as “Post inflammatory Hypo-pigmentation” after anything causing inflammatory changes on skin. To explain you simply the condition: you should know that we have our skin divided into multiple layers. The most superficial layer is known as "epidermis". This layer contains the special cells known as "melanocytes" which produces color giving pigment known as "melanin".

In normal circumstances these secrete or produce the melanin pigment (the pigment because of which we have our own body color) according to its own normal capacity. But in certain situations, where there is some injury or inflammation is present then that area heals with this phenomenon of hypo (less) or hyper (high) pigmentation according to the activity of melanocytes.

Now in case of “Post inflammatory Hypo-pigmentation" melanocytes produce less color due to slight temporary damage to the skin. This temporary damage to the skin can be due to friction or slight trauma over anywhere on skin. In your daughter I can make out that the swimming itself caused mild inflammation.

The good proof for the same is the itching and spreading appearance. As you applied cortisone then the skin got hypo-pigmentation with itself as well as a normal natural phenomenon of peeling of skin. You can see that there are very small eruptions at the affected areas. You just can see that the area of the skin is not exactly white but is diffusely white with very mild scaling. Let me further reassure you that it is a totally reversible condition and gets better without any medications or active interventions.

In my patients with your kind of situation I first reassure the parents and then even if the parents are really worried then I suggest to apply a simple moisturizer cream for 2-3 times. I also suggest you to not to apply any steroid cream now as it can get further hypopigmented.

Over all to guide you finally you should not be worried about this condition as is totally simple and usual condition which we see in day to day life and are very well treatable conditions.

I hope these information's will help you. If you have further queries I will be happy to help.

"Wish you good health"

Regards,
Dr Sanjay Kumar Kanodia
MD (Dermatology)

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