Dr Keith Hopcroft continues our series of fascinating but often unrecognised conditions
‘His eczema's getting no better,' says the mother of the 12-year- old boy, rolling up his sleeves to show me. ‘Can we try a different cream?'
A glance at his notes confirms he's been prescribed a number of emollients and some mild steroid creams.
He's had the problem for a couple of years, and mum mentions that his father had very similar trouble as a child.
I expect him to present his antecubital fossae to me, given that this is the usual site for eczema. But he goes on rolling up his sleeves to reveal his upper arms. Mum tells me his thighs are affected in exactly the same way.
On examination he has a widespread rash on both upper outer arms, which looks like a low-grade folliculitis. The skin is dry and has a slight sandpaper feel.
The diagnosis
This wasn't eczema, but keratosis pilaris – a very common skin disorder affecting children and adolescents. Some authorities put the prevalence as high as 50-80%, though it's not often presented to the GP. The cause is a hyperkeratotic process that blocks hair follicles and causes mild inflammation.
Typical features
Keratosis pilaris results in multiple small, keratotic papules, with slight reddening around hair follicles. This results in a characteristically rough feel to the surface of the skin. The distribution is typical, usually involving the upper outer arms and thighs. It is thought to be autosomal dominant in inheritance, so a positive family history is common.
Treatment
In the vast majority of cases, reassurance is the only treatment needed. The patient and parents can be reassured that the problem tends to resolve in adulthood. In those significantly troubled by the rash, salicyclic acid 2-4% in emulsifying ointment, and the use of an abrasive pad, may help.
Issues for the GP
Although treatment is of limited benefit and unnecessary in most cases, a positive diagnosis of keratosis pilaris is worthwhile. Not only can patients be reassured that the condition is a harmless nuisance that will resolve in time, they can stop a futile merry-go-round of over-the-counter or prescription creams.
Take home point
Not all ‘dry' skin in children is a manifestation of eczema. A re-examination and consideration of the distribution should reveal the diagnosis when the real problem is keratosis pilaris.
Dr Keith Hopcroft is a GP in Laindon, Essex
Keratosis pilaris Keratosis pilaris
