a) take a scraping of the crusts to send for culture, fungal and bacterial.

a) True _ _ _ _ _ _ _ _ _ _ Correct. Anything else? ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯

b) change fungal cream to a different formulation.

b) True _ _ _ _ _ _ _ _ _ _ Wrong answer ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯

c) try a topical steroid ointment.

c) True _ _ _ _ _ _ _ _ _ _ Correct. Anything else? ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯

d) try a topical steroid cream.

d) True _ _ _ _ _ _ _ _ _ _ Wrong answer ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯

e) take a good look at his scalp and nails and enquire about family history.

e) True _ _ _ _ _ _ _ _ _ _ Correct. Anything else? ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯

f) do a throat swab.

f) True _ _ _ _ _ _ _ _ _ _ Correct. Anything else? ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯

Answer and Commentary _ _ _ _ _ _ _ _ _ _ The history is compatible with plaque-type psoriasis. The clues are a well-demarcated rash with scales. Psoriasis often responds a little to any form of cream or moisturizer, but then it quickly becomes ineffective. Other possibilities are lichen planus which tends to be pruritic and lichenifies rather than scales. Atopic dermatitis can also be considered, however it is generally on the flexoral surfaces and also tends to be more pruritic and not very scaly. A fungal infection likely would have responded to some extent and is rarely scaly except on the scalp. Psoriasis often gives a prolonged history or is associated with recent streptococcal infection when it presents for the first time. Frequently there is a family history. Ointment is preferable to cream as it penetrates more effectively and moisturizes the skin at the same time. ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯ ¯