Type I

• classic adult form
• makes up 60% of cases
• good prognosis with 80% involuting after 3 years

Type II

• juvenile-onset (3 forms)
• make up 40% of cases
• poorer prognosis for involuting

1. Prodrome

• insidious onset with diffuse scaling and erythema of the scalp

2. Primary Rash

• a firm acuminate, tiny papule, reddish-brown in colour topped by a central keratotic (horny) plug pierced by a vellus hair
• masses of these papules coalesce to form large erythematous sharply demarcated plaques within which islands of normal skin can be found
• initially found on the sides of the neck, the trunk, and on the extensor surfaces of the extremities but then extensive areas become involved which look like exaggerated goose-flesh and feel like a nutmeg grater
• rash takes on an orange salmon-yellow colour
• may be pruritic and the Koebner phenomenon may be present, i.e., new onset of lesions at the site of trauma

3. Others

• thick hyperkeratosis of the palms and soles with a tendency to fissure (may get a sandal-like plantar hyperkeratosis)
• nails - dull, rough, thickened, brittle, striated, but pitting is not evident