This week, genito-urinary specialist Dr Derek Freedman tackles rashes, sores and other nasties. More next week. . .

Are genital rashes caused by sexually transmitted infections?

Some are, some are not. We so often forget that the genitalia are only flaps of skin and suffer the same conditions of skin anywhere else on the body. Sometimes skin conditions in this area can look different because of the moist nature of the local environment.

What conditions are sexually transmitted?

Pubic lice, scabies, Molluscum Contagiosum.

Do pubic lice actually jump?

No, they only survive in the warm microclimate of the pubic environment and are attached to the pubic hair. They are transmitted by close body contact, as when the pubic hair of the two individuals are in close and intimate contact. You do not get them from toilet seats! We very seldom see them today. The popularity of

bikini waxing means there is no longer an ecosystem to support their survival -- they could be considered an endangered species!

How soon after you catch them can you see them?

Usually it takes two to four weeks for the eggs to incubate and hatch. Then you get the itch, and you can see the little nits on the hair.

How do you treat them?

With a lotion usually -- they clear well. But catching pubic lice is a reminder to have a full STI screen to make sure you did not catch any other infection. Your partner(s) should also be treated.

Can scabies be sexually transmitted?

Of course it can. Again, close skin-to-skin contact allows the mite to transfer from one person to another. The mite burrows into the skin, lays eggs and the offspring make burrows in the skin. A couple of weeks later you see a rash, and become itchy all over the body. This is due to the mite excrement causing an allergic reaction. It is usually worse at night; the heat of bedclothes brings out the irritation.

I have heard that it can be hard to clear?

The mite usually clears quickly with a special lotion, but the allergic reaction can persist for a few weeks, causing a continuing itch that requires additional treatment.

Got a question for Dr Freedman? Write in confidence to Streetwise, Evening Herald Features, 27-32 Talbot Street, Dublin 1. If you're worried you might have an STI, contact St James's Hospital GUIDE clinic on 01 416 2315/416 2316. Treatment is free of charge

- Dr Derek Freedman