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Mixed diagnoses – 10 cases (3 of 11)

For each of the ten cases, study the image(s) and then answer the questions. You can click on the image to view a larger version if required.

Each case should take approximately five minutes to complete. There is a list of suggested further reading material at the end of the quiz.

When you finish the quiz, you can download a certificate.

Case 2

A 37-year-old man presents with marked scaling in his scalp. He says he has used an anti-dandruff shampoo twice weekly for many years, but it is no longer effective. He attributes the problem to stress.

There is a large patch of thick white scale in the scalp with sticky asbestos-like scales matting the hair shafts. This appearance is known as 'pityriasis amiantacea'.

Pityriasis amiantacea can be due to bacterial infection (Staphylococcus aureus or Streptococcus pyogenes), in which case the underlying scalp is red and moist. More frequently, seborrhoeic dermatitis or psoriasis is responsible.

The mass of scale must be removed by applications of a tar or keratolytic agent such as coconut oil compound ointment, washed out after an hour or so with a tar shampoo. If the patient does not tolerate tar, prescribe salicylic acid 4% in aqueous cream and ketoconazole shampoo. Repeat daily until clear, then twice weekly as necessary.

The underlying skin disease may need long term treatment. This patient had psoriasis and was later prescribed calcitriol solution to use on the affected areas twice daily.

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