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Keratosis pilaris

25 April 2012, by MAZEREEUW-HAUTIER J. & BONAFÉ J.-L.


Keratosis pilaris is a common disorder presenting clinically as greyish bumps or lumps located in the follicular ostia which give the skin a rough feel.


This is a harmless, common autosomal dominant disorder with variable penetrance that is more frequently observed in women. The lumps are mainly located on the outer sides of the arms and thighs and the cheeks. The skin around the follicle may become inflamed and red. These rough bumps appear in childhood and, in most cases, will have disappeared by the time the child reaches adulthood ; half of sufferers observe an improvement in the summer months. Individuals who have keratosis pilaris often also present with ichthyosis vulgaris and atopic skin. A genetic cause is suspected owing to the connection between keratosis pilaris and partial monosomy of chromosome 18 [1].

Histology contributes little (hyperkeratosis of the pilar ostia) and the condition does not have an impact on laboratory test results. It is a totally harmless but sometimes unsightly condition.


Acquired keratosis pilaris can occur with numerous dermatological conditions including follicular lichen planus, follicular psoriasis, follicular tuberculides, follicular eczema, follicular sarcoidosis, follicular mucinosis, dermatomyositis, vitamin A or C (scurvy) deficiency, spinulosis from secondary syphilis, certain pilar dysplasias (monilethrix, pili torti, Marie Unna hereditary hypotrichosis) and acrokeratosis verruciformis of Hopf.


Keratosis pilaris atrophicans is characterised by typical follicular keratosis lesions which become atrophied, leaving permanent scarring.

It is part of a variety of syndromes [2] including ulerythema ophryogenes, Siemens’ syndrome, atrophodermia vermiculata of the cheeks and Quinquaud’s decalvans folliculitis.

These syndromes can be differentiated by their localisation and the severity of the inflammation they cause. Other authors consider these various syndromes to be a single clinical entity.


It is a harmless condition. Treatment is aimed at providing temporary symptomatic relief. Keratosis pilaris tends to improve with age. However, the skin damage caused by keratosis pilaris atrophicans is permanent.

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