Scaly skin conditions

Skin diseases that have excessive scale or flaking (papulosquamous disorders) are due to epidermal inflammation or proliferation. We list localised and generalised scaly skin disorders by their duration and body site. 

Localised scaly rash present for < 6 weeks

Dermatophyte infections

• Irregular annular rash with peripheral scale
• Acute forms of tinea may also have follicular pustules
• Tinea corporis – trunk, limbs
• Tinea cruris – groin
• Tinea pedis – feet
• Tinea manuum – hands
• Tinea faciei – face

Generalised scaly rash present for <6 weeks with fever

Scarlet fever

• Scarlatiniform rash (redness then rough spots)
• Strawberry tongue
• Peeling starts after 5 days of illness
• Evidence of streptococcal infection

Kawasaki syndrome

• Child aged < 14 years
• Starts as morbilliform or erythematous rash
• Swelling of hands and feet
• Oral and ocular signs
• Lymphadenopathy

Exfoliative dermatitis

• Scaling stage of erythroderma
• Starts as morbilliform rash or other pattern
• Often drug-induced

Generalised scaly rash present for < 6 weeks without fever

Pityriasis rosea

• Herald patch
• Oval 2–4 cm pink plaques on trunk with peripheral, trailing scale
• Spares scalp, peripheries

Acute guttate psoriasis

• Round 0.5–3 cm red plaques with diffuse scale
• Trunk > limbs
• May involve all body sites

Pityriasiform or lichenoid drug eruption

• New drug (eg hydroxychloroquine)

Localised scaly rash present for > 6 weeks

Seborrhoeic dermatitis

• In and around hair-bearing scalp, eyebrows, hairy chest
• Skin folds behind ears, nasolabial fold, axilla
• Salmon pink, flaky

Psoriasis

• Localised variant
• Scalp, elbows, knees or palms and soles

Discoid lupus erythematosus

• Face, ears, scalp > upper trunk, hands
• Scale is due to plugged follicles
• Leads to scarring

Pityriasis versicolor

• Flaky rash on trunk
• White, red, brown variants

Keratosis pilaris

• Upper arms > thighs > cheeks
• Hair follicles plugged with scale

Annular erythema

• Crops of slowly enlarging erythematous annular plaques on trunk
• Trailing scale

Palmoplantar keratoderma

• Thickened skin of palms and soles
• Congenital and acquired, punctate and diffuse variants

Crusted scabies

• Scale is prominent between fingers, elbows, scalp
• May or may not be very itchy
• Contacts have scabies

Widespread tinea corporis

• Irregular annular plaques
• Peripheral scale

Ichthyosis

• Dry skin (see below)

Chronic plaque psoriasis

• Symmetrical well-circumscribed plaques with silvery scale
• Generalised large or small plaques

Lichen planus

• Bilateral but asymmetrical firm papules, plaques
• Polygonal shape
• Scale is variable

Pityriasis lichenoides

• Trunk and limbs
• Skin coloured or red flat or indurated papules/small plaques
• Mica scale (peels off in one sheet)

Pityriasis rubra pilaris

• Psoriasis-like symmetrical or erythrodermic scaly rash
• Orange-red hue
• Follicular prominence

Cutaneous T cell lymphoma

• Slowly evolving slightly scaly annular and roundish patches, plaques and sometimes nodules
• Various morphologies including erythroderma
• Buttocks, breasts common initial sites

Dermatitis neglecta

• Build-up of scale due to avoidance of washing

Scaly condition by body site

Solitary scaly lesions

• Actinic (solar) keratoses
• Basal cell carcinoma (superficial)
• Bowen disease (intraepidermal squamous cell carcinoma) 
• Squamous cell carcinoma
• Keratoacanthoma

Scaly Scalp

• Pityriasis amiantacea
• Cradle cap
• Seborrhoeic dermatitis
• Scalp psoriasis
• Tinea capitis
• Cutaneous lupus erythematosus
• Seborrhoeic dermatitis

Scaly patches on the face

• Seborrhoeic dermatitis
• Facial psoriasis
• Atopic dermatitis
• Lupus erythematosus
• Pityriasis alba

Scaly patches on arms and legs

• Pityriasis alba
• Disseminated superficial actinic porokeratosis
• Porokeratosis of Mibelli
• Keratosis circumscripta
• Flegel disease
• Kyrle disease
• Lichen striatus
• Pellagra

Scaly skin folds

• Intertrigo
• Seborrhoeic dermatitis
• Flexural psoriasis
• Erythrasma
• Confluent and reticulated papillomatosis
• Granular parakeratosis

Scaly patches on the trunk

• Pityriasis rosea
• Darier disease
• Grover disease
• Pityriasis versicolor
• Porokeratosis ptychotropica (buttocks)

Scaly patches anywhere or everywhere

• Dry skin
• Dermatitis (Eczema)
• Atopic dermatitis (eczema)
• Tinea infections
• Psoriasis
• Paediatric psoriasis. Psoriasis in children
• Lichen planus
• Ichthyosis
• Ichthyosis vulgaris
• Recessive X-linked ichthyosis
• Netherton syndrome
• Harlequin ichthyosis
• Collodion baby
• Chronic superficial scaly dermatosis (parapsoriasis)
• Cutaneous T-cell lymphoma
• Erythrokeratoderma
• Pityriasis lichenoides
• Pityriasis rotunda
• Pityriasis rubra pilaris
• Reiter syndrome
• Subcorneal pustular dermatosis (Sneddon Wilkinson disease) 
• Secondary syphilis

Scaly palms and soles

• Acrodermatitis continua of Hallopeau
• Cracked heels
• Corn and callus
• Juvenile plantar dermatosis
• Exfoliative keratolysis
• Pompholyx
• Palmoplantar psoriasis
• Keratoderma
• Acquired keratoderma
• Diffuse hereditary keratoderma
• Pachyonychia congenita
• Parakeratosis pustulosa
• Punctate keratoderma
• Focal hereditary keratoderma
• Acrokeratoelastoidosis
• Porokeratotic eccrine ostial dermal duct naevus