Definition
- Common benign skin condition.
- Caused by keratin build-up in hair follicles.
- Name:
- Keratosis = scaly skin
- Pilaris = related to hair
Epidemiology
- Affects 50–70% of adolescents, ~40% of adults.
- More noticeable during childhood and adolescence.
- Associated with:
- Atopic dermatitis
- Ichthyosis
- Filaggrin gene mutations (autosomal dominant inheritance)
Pathophysiology
- Abnormal keratinisation of upper follicular epithelium.
- Leads to keratin plugging of hair follicles.
- Worse in cold, dry weather (e.g., winter).
Clinical Features
- “Goosebump” / “chicken skin” appearance.
- Tiny, rough, skin-coloured or erythematous papules.
- Most common sites:
- Extensor arms and thighs
- Buttocks, face, trunk, chest
- Skin may feel dry, rough, and occasionally itchy.
- May have surrounding erythema or pigmentation.
- Special variants:
- Keratosis pilaris rubra – erythematous form
- Ulerythema ophryogenes – eyebrow involvement with scarring
- Atrophoderma vermiculatum – cheek atrophy
Skin Type Variation
- Papules:
- Red in light skin
- Brown/black in darker skin
Complications
- Atrophy
- Scarring, possibly with hair loss
Diagnosis
- Clinical diagnosis
- Dermoscopy:
- Short/coiled hair, follicular plugging, erythema, scaling
- Biopsy (rarely needed):
- Hyperkeratosis, plugged follicles, mild lymphocytic infiltrate
Differential Diagnosis
- Atopic dermatitis
- Folliculitis
- Milia
- Lichen nitidus
- Lichen spinulosus
- Phrynoderma (vitamin A deficiency)
Management
General Measures
- Regular use of exfoliating sponges/scrubs
- Avoid harsh soaps and prolonged hot showers
Topical Treatments
- Moisturisers with keratolytics:
- Urea
- Lactic acid
- Salicylic acid
- Glycolic acid
- Topical retinoids (e.g. adapalene, tretinoin)
- Short-course topical corticosteroids for inflammation/itch
Procedural Therapies
- Pulsed dye laser / IPL – for erythema
- Laser hair removal – for follicular plugging/ingrown hairs
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