Keratosis Pilaris (KP)

Keratosis pilaris is a very common, benign follicular keratosis often described as "goosebump" or "chicken skin" due to keratin plugs blocking hair follicles. It has a strong link to atopic dermatitis and dry skin conditions.

• Onset & Course: Usually starts in childhood and often worsens around puberty. It is chronic, and tends to be worse in cold, dry weather.

• Symptoms: The primary complaint is rough, bumpy skin that feels like "sandpaper." It is usually asymptomatic, but can be mildly itchy.

• Distribution: Classically on the posterolateral upper arms and anterior thighs. Also common on the buttocks and cheeks (in children).

Skin of Colour Points:

• Patients may describe "dark dots" or uneven tone rather than just red bumps.

• Picking or harsh scrubbing easily leads to Post-Inflammatory Hyperpigmentation (PIH), which is more visible and slower to fade in darker skin tones.

• Lesions: 

Numerous tiny (approx 1 mm) follicular keratotic papules centred on hair follicles. The surface is rough and dry.

• Colour:

  • Light skin: Skin-coloured or white papules with a red perifollicular halo.

  • Darker skin: Papules may be skin-coloured or lighter, with brown/dark perifollicular discolouration instead of obvious redness, giving an overall "speckled" look.

• Sites: Extensor upper arms, front of thighs, and buttocks are classic sites.

The key message is that KP is benign and chronic. Treatment aims to improve texture and pigment, requiring ongoing maintenance.

1. General / Skincare Measures

• Reassurance: Explain that KP is harmless and very common. Set expectations that complete clearance is difficult to achieve.

• Gentle Skincare: Use mild, fragrance-free cleansers.

• Moisturise Daily: Apply a thick cream or ointment after bathing onto damp skin.

• Avoid Irritation: Do not use vigorous scrubbing or harsh physical exfoliants, as this increases irritation and PIH risk, especially in darker skin.

2. First-line Topical Therapy

The goal is to smooth roughness and clear follicular plugging using keratolytic moisturisers.

• Keratolytics:

  • Urea 10%–20% creams.

  • Lactic acid or glycolic acid (Alpha-Hydroxy Acids).

  • Salicylic acid (Beta-Hydroxy Acid).

• Skin of Colour Adaptation: Start slowly (e.g., every other night) to avoid irritant dermatitis and subsequent PIH. Always combine with or layer over a bland moisturiser.

3. Second-line / Specialist Treatments

Used when first-line fails or the cosmetic impact is high.

• Topical Retinoids: (e.g., Tretinoin, Tazarotene) help normalise keratinisation but are often irritating. In darker skin, start at a very low frequency to avoid irritation that worsens hyperpigmentation.

• Lasers / Peels: Chemical peels (high-strength glycolic acid) or laser therapies (e.g., Nd:YAG for darker skin) may be used by specialists to target redness, roughness, and pigmentation, but carry a risk of hypo- or hyperpigmentation.

Skinsight - Keratosis Pilaris: https://skinsight.com/skin-conditions/keratosis-pilaris/

StatPearls (NCBI Bookshelf) - Keratosis Pilaris (Pennycook & McCready, 2023): https://www.ncbi.nlm.nih.gov/books/NBK546708/

DermNet NZ - Keratosis Pilaris (Winter & Motley, 2022): https://dermnetnz.org/topics/keratosis-pilaris