Overview

Keratosis Pilaris (KP) is a common skin condition which looks like small bumps on your skin. They tend to appear in areas such as your arms, thighs, cheeks, or buttocks. This occurs because of a buildup of a protein that helps your fingernails, hair and skin form and grow called keratin. This clogs the pores in your skin, causing these bumps. Though this condition is harmless, it can be chronic, and the bumps can be itchy and red. 

KP affects people of all ages, though it is more common in teenagers and causes cosmetic concern and often makes people feel self-conscious and bad about their skin. There is no cure for the condition, but it can be treated with moisturisers and other skin care products to reduce its appearance.^1,2,3

The causes of keratosis pilaris are still unclear, although it could be due to genetics.^1,2,3 Recent research shows that there may be a link between KP starting and deficiencies in vitamins such as A and D. These are vitamins important in keeping our skin healthy and help our skin cells renew. Research findings show that KP symptoms may improve with taking vitamin supplements. This article will look at the importance of understanding the links between vitamin deficiencies and the roles of vitamins A and D within skin and keratosis pilaris, and the possible treatment options.

What is Keratosis Pilaris?

Keratosis pilaris is a benign (harmless) skin condition caused by a buildup of a protein called keratin that helps your fingernails, hair and skin form and grow. In this condition, the keratin clogs the hair follicles in your skin, causing them to raise and form small bumps on your skin. This condition is also called “chicken skin” because the bumps look like goosebumps (like when you get cold). Common areas for these bumps to form are your upper arms, thighs, cheeks and buttocks, but they can also appear on any part of your body that has hair.^1,2,3

Keratosis pilaris is a common condition and can affect anyone from babies to children to teenagers to adults of any race. However, it is most common in teenagers, with the condition typically worsening during puberty. 50% to 80% of teenagers and 40% of adults develop KP at some point during their lives.¹

Symptoms of Keratosis Pilaris

The main symptoms of keratosis pilaris present as small, raised bumps on the skin; the bumps tend to be the same colour as your skin but can also appear to be red in colour. Usually, this does not feel irritating or painful, just rough to the touch; however, you can sometimes experience other symptoms such as:^1,2,3

• There can be seasonal variation, bumps get better in the summer and worse in the winter due to low humidity and drier air
• Rough and sandpaper-like skin where the bumps are
• Itchy or dry skin
• Irritation of the bumps causing discolouration (frictional lichenoid dermatitis)

Causes of Keratosis Pilaris

Exact causes of keratosis pilaris are unknown and are likely to be caused by several different factors, such as genetics, environmental factors, such as cold and dry air, which decrease skin hydration, leading to dry skin, which is more likely to trigger KP and nutrients such as vitamins.

However, you are more likely to have the condition if someone in your family has it, suggesting the cause may be genetic. Research has found that there may be links with mutations to the ABCA12 gene, which is key in skin development, the filaggrin (FLG) gene, which is key in skin structure and function and abnormalities in chromosome 18 with keratosis pilaris.⁴

There are also some genetic traits which doctors and researchers think might make you more likely to develop KP, such as if you have 1:

• Skin conditions like eczema, atopic dermatitis or ichthyosis vulgaris²
• Fair or pale skin
• Diabetes
• Asthma
• An underactive thyroid (Hypothyroidism)
• Cushing’s syndrome
• Obesity
• Down syndrome

Another potential cause of or link to keratosis pilaris is if you have a deficiency in vitamins A and/or D. This may not directly cause KP, but could make the condition worse or make recovery harder.

The role of Vitamin A in skin and keratosis pilaris

Vitamin A is also known as retinol or retinoic acid and is a nutrient our body uses, important in:^5,6

• Helping to keep skin healthy and generate new skin cells
• Helping your vision in low light
• Helping your body’s immune system work against illness and infection

The daily amount of vitamin A you should be having is 900 micrograms for men and 700 micrograms for women.⁶

Whilst there is limited research currently, there is scientific evidence that suggests it might not be a direct cause but rather a link between people who have a lack of vitamin A and developing keratosis pilaris-like symptoms, with patients showing improvement after taking vitamin A supplementation either orally or through topical retinoid creams.⁷

The role of Vitamin D in skin and keratosis pilaris

Vitamin D is an essential nutrient also known as calciferol and is used by your body to:^8,9

• Maintain the balance of calcium in your blood and bones
• Bone development and maintenance
• Support immune health
• Keeps our muscles and brain cells healthy
• Keep skin healthy and help keratinocytes mature, which produce keratin

The daily amount of vitamin D you should be having is 400 international units (IU) for children and between 600 - 800 IU for adults.⁹

Research on the link between vitamin D deficiency and keratosis pilaris is limited, but there does seem to be a link between the two, as patients who have vitamin D deficiency have more skin conditions, such as other forms of keratosis, compared to those who are healthy.¹⁰

Diagnosis of Keratosis Pilaris

If you think you have keratosis pilaris, you should see your GP or a dermatologist. They will likely be able to diagnose you without any testing, just with a simple examination of your skin where the bumps are, since the condition is easy to recognise. If they are unsure if you have the condition or not, they may refer you for further testing, such as an allergy test or a skin biopsy.

Testing vitamin levels is not currently standard to assess whether you may have KP or not; however, looking at your vitamin A and D levels could offer additional value in persistent or treatment-resistant cases. Currently, there is too little evidence, and it would cost more to include vitamin testing in regular screening for KP, but it could be useful in certain conditions where it is harder to diagnose, such as those with eczema or those who have issues with absorbing food (malabsorption syndrome).

Treatment and Management of Keratosis Pilaris

Keratosis pilaris will sometimes clear up on its own and doesn’t always need treatment, but many treatment options can help manage KP. Your dermatologist or GP will be able to recommend the right kind of treatment for you, which can range from moisturising creams to lotions and other bathing products, or other medicated, stronger products. Treatments can include:

• Using moisturising creams or lotions daily^1,3
• Using gentle exfoliating soaps or body wash^1,3
• Laser treatments^1,3
• Using medicated prescription strength or steroid creams that contain ingredients such as urea, alpha hydroxy acids, salicylic acid, lactic acid and glycolic acid - these are also called topical exfoliants^1,2,3
• Using over-the-counter moisturising lotions that contain ingredients such as ammonium lactate and alpha hydroxyl acids, such as AMLactin or CeraVe SA¹

In terms of potential vitamin A and D deficiency-related KP, there are some treatments you can use alongside the other usual recommended treatments listed above, which can range from creams to supplemental pills such as:

• Medicated vitamin A creams, often called topical retinoids such as tretinoin (Retin-A, Renova, Avita and Altreno, etc.) and tazarotene (Tazorac, Avage, Arazlo, etc.), which can decrease the buildup of keratin in your pores and help you replace your skin cells quicker^1,2
• Taking oral vitamin A supplements, such as fish liver oil or pills⁵
• Taking oral vitamin D supplements
• Eating foods that contain vitamin A, such as dairy, eggs, yellow/orange vegetables, oily fish and liver products such as pâté⁵
• Eating food that contains vitamin D, such as fortified milk and cereals, and fish such as salmon and mackerel⁹

It is important to know that vitamin A and D supplementation should be used or taken in moderation; too much could cause more harm than good. Talk to your doctor about an appropriate amount you should be consuming.

Other things you can do yourself at home to help your KP alongside your moisturisers and prescribed treatments are:

• Having cool or lukewarm, instead of hot in temperature showers or baths^1,3
• Using a loofah, washcloth or exfoliating mitt to gently scrub your skin^1,3
• Using natural exfoliant home remedy products, such as applying apple cider vinegar, baking soda or coconut oil to the affected area and rubbing in a small circular motion for a few minutes¹
• Stay hydrated and drink plenty of water and other fluids, and use a humidifier to keep your skin hydrated^1,3
• Don’t rub hard, pick at, scratch or try to pop any of the bumps to prevent scarring and infection^1,3
• Having a balanced diet to get more vitamin A and D in^5,6
• Being exposed to sunlight to get more vitamin D^8,9

Summary

Keratosis pilaris is a common and harmless skin condition where bumps form on the surface of your skin, often on your arms and legs, caused by too much keratin clogging up your pores. Though its exact cause is unknown, it is likely due to genetic factors and tends to run in families; however, there does seem to be links with vitamin A and D deficiencies and developing the condition. Vitamin A supports skin cell regeneration, and vitamin D is important in skin health and overall immune health. Whilst there is no cure, management of the condition can involve treatments such as supplementation of these vitamins either through oral supplements or diet and should be used alongside other moisturisers and creams.