Keratosis pilaris is a benign skin condition that’s usually referred to as “chicken skin.” Studies suggest that it occurs when there’s an excessive amount of keratin proteins on the skin.1 To give you a background, keratin is a type of filament protein, which is responsible for holding skin cells together and forming the outermost layer of the skin. By doing so, it protects the body against foreign contaminants and keeps the skin from pulling apart.2
Excess keratin proteins may build up and clog the hair follicles, causing them to thicken and form into small bumps.3 Keratinization may also dilate the small blood vessels located in the upper skin layers, giving the appearance of red or flushed skin.4 Researchers have yet to find the exact causes that trigger keratinization of hair follicles despite the prevalence of keratosis pilaris in various subpopulations.5
What Does Keratosis Pilaris Look Like and Which Body Parts Does It Affect?
Keratosis pilaris is characterized by numerous tiny bumps that come in red and/or tan colors. Some bumps may also have a light-red halo, which indicates inflammation. The number of bumps scattered in an affected area may vary from around 10 pieces to more than a hundred, giving the skin a patchy appearance and an irregular sandpaper-like texture.6
The telltale sign of keratosis pilaris may occur on any body part that has hair follicles. Unfortunately, hair follicles are found all throughout the body except the palms, soles and mucocutaneous areas.7
The good news is that it’s rare for keratosis pilaris to affect the entire body.8 According to studies, 92 percent of sufferers develop keratosis pilaris on the back of their upper arms, while those that experience the symptoms on their thighs and buttocks are approximately 59 and 30 percent, respectively.9 Some cases of keratosis pilaris also affect the back, legs, face and scalp.10
The Different Types of Keratosis Pilaris
Keratosis pilaris is classified according to the type and extent of its symptoms. The three common types of this condition are:11
- Keratosis pilaris rubra: This is a common form of keratosis pilaris wherein the bumps appear red and inflamed. The extent of affected skin is also larger than the other forms of this skin condition.12
- Keratosis pilaris alba: This type of keratosis pilaris is characterized by dry and rough patches of skin, but without any irritation.13
- Keratosis pilaris rubra faceii: This form of keratosis pilaris is similar to rosacea in appearance, since it’s characterized by red rashes on the cheeks.14
The other less common variants of this skin condition include keratosis pilaris atrophicans faciei (KPAF) and atrophodermia vermiculata.15 KPAF causes bumps around the eyebrows and cheeks of infants before spreading around the face,16 whereas atrophodermia vermiculata manifests as a honey-combed reticular atrophy on the cheeks.17
The Statistics on Keratosis Pilaris: How Many Are Affected by This Skin Affliction?
Keratosis pilaris is an extremely prevalent condition all over the world. It may occur at any age, but it’s more common in children and adolescents. According to the American Academy of Dermatology, a person is likely to develop this condition before 2 years of age or during their teenage years.18
Studies also show that keratosis pilaris affects approximately 50 to 80 percent of adolescents and 40 percent of adults worldwide, further confirming that this condition is indeed more prevalent in children and adolescents than adults.19 Children usually outgrow this condition by the time they reach their adolescent years. However, hormones may cause keratosis pilaris to flare up during puberty. Adults between 40 to 50 years old may still develop it as well.20
A study published in the International Journal of Trichology also suggests that women are more likely to develop this condition, with a male to female ratio of 1:2.21
Keratosis Pilaris May Be Mistaken for Other Skin Conditions
Because of its inflamed appearance, it’s not unusual for some people to mistake keratosis pilaris for pimples. While both of these skin conditions are extremely frustrating, this is where their similarities end.
Keep in mind that pimples are painful while bumps from keratosis pilaris are not — they’re simply itchy.22 It’s also common for some people to pop their own pimple (although this habit is highly discouraged). This practice must avoided for keratosis pilaris since popping it only causes inflammation and scarring.23
Some of the other common skin conditions that may also resemble keratosis pilaris include milia, folliculitis, facial rosacea and xerosis, among others. It even shares a resemblance to some uncommon skin disorders, such as lichen spinulosus, ichthyosis vulgaris and Kyrle disease.24
It’s important to consult a doctor if you’ve been seeing patches of red or tan bumps on your skin to verify the exact skin condition that you have and determine the best treatment methods for your needs.