What Causes Keratosis Pilaris?

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What Causes Keratosis Pilaris?

Keratosis pilaris is a condition of the skin caused by the excessive production of keratin, which is the main protein found in the external layer of human skin and also the main structural element in hair and nails. All this extra keratin produced by your body builds up inside your pores and traps hair follicles. The keratin forms hard plugs – a process referred to as hyperkeratinization – leading to bumps forming. The bumps can be various colors, namely the same color as your skin or red or brown. Keratin itself is cream in color, which is sometimes why the bumps might resemble white heads.

The excess keratin the body produces builds up in the pores and traps hair follicles, leading to hyperkeratinization – a process in which hard plugs are formed. The buildup of keratin forms the bumps that are one of the main symptoms of keratosis pilaris.

Many of these bumps contain an ingrown hair coiled up inside them because the hardened keratin plugs the pore, thereby stopping the hair from growing out of the skin. The hair grows trapped inside the follicle, which is why many of these bumps can become inflamed and often feature a pinkish hue.

The precise cause of keratosis pilaris is unknown, though it has been observed that it does run in families, which is why it is assumed that it is a genetic condition.

Variants of Keratosis Pilaris

There are variations of keratosis pilaris, usually differentiated by the way the condition presents. These variants are as follows:

  • Keratosis pilaris rubra, which is characterized by reddened lesions – basically red patches on the skin along with the spiky bumps;
  • Keratosis pilaris atrophicans faciei, which is characterized by facial follicular atrophy or small depressions that resemble scars;
  • Ulerythema ophrogenes, in which the upper area of the eyebrows is also affected;
  • Atrophoderma vermiculata. In this variant, the cheeks look as if they’ve been eaten by worms;
  • Keratosis follicularis spinulosa decalvans, which is quite rare and presents with bald patches on the scalp and eyebrows;
  • Lichen spinulosus or keratosis spinulosa, which is characterized by single or multiple areas of follicular papules (skin bumps with hair projecting from the center) that each feature a horny spine. These can appear anywhere on the body.

Who Is Affected by Keratosis Pilaris?

Keratosis pilaris seems to affect a lot of children and adolescents, but also presents in many adults. Thus, studies estimate that at least one in two adolescents get keratosis pilaris, while approximately 40% of adults suffer from this condition.

Generally, keratosis pilaris becomes apparent sometime within the first ten years of life and can get worse once puberty sets in. However, this doesn’t mean keratosis pilaris can’t develop later in life.

This condition seems to also develop in people with atopic dermatitis as well as those who have very dry skin. Note that most people who develop the condition have another family member with the same problem, which lends credence to the concept that keratosis pilaris is a genetic condition.


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