Keratinocytes

Looks like

The main cells of the epidermis, making up about nine in ten of its cells; under a microscope, stacked layers flattening as they rise.

What it does

Build the skin's barrier by making keratin; each one moves up from the base and is shed in about a month.

Keeping it well

Sunburn damages their DNA; most skin cancers (basal and squamous cell) arise from them. A scaly patch or sore that does not heal needs checking.

Related conditions

• Acne vulgaris
• Alopecia (androgenetic & areata)
• Atopic dermatitis (eczema)
• Body dysmorphic disorder
• Boils and folliculitis
• Bullous pemphigoid
• Burns
• Candida & fungal infection
• Cellulitis
• Chickenpox (varicella)
• Chilblains (pernio)
• Cold sores (herpes simplex)
• Contact dermatitis
• Endemic fungal infections (histoplasmosis, coccidioidomycosis)
• Epidermoid (sebaceous) cyst
• Fungal skin infection (tinea)
• Hand, foot and mouth disease
• Heat exhaustion & heatstroke
• Hidradenitis suppurativa
• Hyperhidrosis
• Hypermobility and Ehlers–Danlos syndromes
• Hypothermia & frostbite
• Infantile haemangioma (strawberry mark)
• Kaposi sarcoma
• Keloid & hypertrophic scars
• Leishmaniasis
• Leprosy (Hansen's disease)
• Lichen planus
• Lichen sclerosus
• Lyme disease
• Mast cell activation & mastocytosis
• Measles
• Melanoma
• Melasma
• Mpox (monkeypox)
• MRSA and resistant staph infection
• Nappy (diaper) rash
• Necrotising fasciitis
• Onchocerciasis (river blindness)
• Parvovirus B19 (fifth disease)
• Pemphigus vulgaris
• Pilonidal sinus
• Pityriasis rosea
• Pressure ulcers & chronic wounds
• Psoriasis
• Psoriatic arthritis
• Radiation injury
• Rosacea
• Roseola (sixth disease)
• Rubella (German measles)
• Scabies & lice
• Scarlet fever
• Scrub typhus & rickettsial infections
• Seborrhoeic dermatitis & dandruff
• Seborrhoeic keratosis
• Shingles (herpes zoster)
• Skin cancer (basal cell & squamous cell)
• Stevens–Johnson syndrome / toxic epidermal necrolysis
• Sun damage & actinic keratosis
• Systemic lupus erythematosus
• Systemic sclerosis (scleroderma)
• Toxic shock syndrome
• Urticaria & angioedema
• Vitamin D deficiency
• Vitiligo
• Warts, molluscum and skin infections