• Symptoms (itching, pain, flexural intertrigo, limitation of manual dexterity), cosmetic problems or both

• Joint pains (psoriatic arthropathy (p. 481); psoriatic arthritis may be found in 10–15% of patients)

• Family history (30% of patients have family history)

• Aggravating factors (emotional stress, overuse of alcohol, streptococcal infections, drugs such as beta-blockers, lithium or tumour necrosis factor-α therapies).

• Well-demarcated salmon pink plaques with silvery white scales (Fig. 152.1) over extensor surfaces, scalp, naval and natal cleft. They often tend to have a pink or red line in the intergluteal fold

• A white blanching ring, known as Woronoff’s ring, may be observed in the skin surrounding a psoriatic plaque.

• Look at the nails for pitting (Fig. 152.2) and onycholysis (separation of the nail plate from the bed; p. 675)