Q (Dec 5) I'm expecting my first baby this month and have a lot of pimples on my back and tummy that the doctor says is due to the hormone changes.

Sometimes the itch is pretty bad and using calamine lotion doesn't help, so I use medicated oil on my tummy. Is it okay to use medicated oil? Will my skin absorb it and will it affect the baby?

I also seem to have a craving for the smell of mothballs! Why is this so?

A Congratulations on your first pregnancy.

It is true that the pimples on your back and tummy are due to hormonal changes and calamine lotion offers only a temporary relief as it cools the skin.

Because of the rise in hormones, the skin can sometimes get very dry during pregnancy. In some women, the sebaceous glands beneath the skin try to compensate by producing more sebum. But instead of lubricating the skin, this causes pimples to erupt, as the duct openings get blocked.

You can try applying a non-perfumed medicated body lotion twice or thrice a day and see if your acne improves. Most of the time, it will. In extreme cases, a short course of antibiotics may be prescribed in conjunction with the topical creams to solve the problem.

Some pregnant women experience a rash that appears as blotches on the skin and is very itchy. This condition is called PUPPP (pruritic urticarial papules and plaques of pregnancy).

This condition is the most common dermatosis (skin condition) of pregnancy. The cause was unknown until recently, when Dr Selim Aracting and his colleagues in France reported studies linking PUPPP with cells from the developing foetus. Their studies suggest that foetal cells can invade the mother's skin during pregnancy and in some way cause this skin disorder to develop.

It typically starts on the tummy and spreads to the thighs. Occasionally it also spreads to buttocks and arms, but the face is always spared.

This commonly occurs in the third trimester - around 34 weeks of pregnancy. It may appear to look like pimples, but the raised bumps itch.

The condition is harmless to both baby and mother and resolves spontaneously after delivery. It is usually treated with steroid creams but, in extreme cases, oral steroids may be prescribed.

It is advisable to see your obstetrician to check if you have this condition.

Regarding the use of medicated oil, it typically contains methylated spirit and salicylate acid, among other ingredients. There is no evidence to show that topical salicylic acid is harmful to a foetus, but small amounts do get absorbed into the expectant mother's skin. The occasional use of medicated oil for headache and mosquito bites is acceptable.

Mothballs contain camphor and naphthalene. In some households, mothballs are used as room deodoriser, which is no longer advisable. This is because prolonged exposure to the naphthalene fumes can cause headaches, nausea and occasional vomiting in anyone heavily exposed to them.

However, in people who have a deficiency in the enzyme glucose-6-phosphate dehydrogenase (known as G6PD Deficiency), prolonged exposure and inhalation of mothballs may cause the red blood cells to break down spontaneously, as the glucose-6-phosphate dehydrogenase (G6PD) enzyme that normally protects the red blood cells from damage are absent.

I suspect that you find the mothball scent refreshing due to the camphor component.

May I suggest you use natural essential oils that are equally strong smelling, like bergamot, citronella or eucalyptus, instead.

Have a safe delivery.

For an appointment at Raffles Hospital, call 6311-1222

DR CORDELIA HAN, CONSULTANT OBSTETRICIAN & GYNAECOLOGIST, RAFFLES HOSPITAL