The answer

It sounds as though Josh has seborrhoeic dermatitis, a condition associated with dandruff that can cause itching and scaling of the skin. The scalp is most likely to be affected, but other areas of the body that are commonly involved include the face, in and around the ears, the chest and upper back, and skin folds such the groin and armpits. Complications include issues with self-confidence and secondary infection – both of which seem to be afflicting Josh – and generalisation of the condition to the whole body. If the scalp if badly affected, there may be some degree of hair loss, though this is usually temporary.

Josh needs to visit his GP as it sounds as though he needs to be prescribed ketoconazole in two forms for a period of at least four weeks: a two per cent shampoo used at least twice a week for his scalp, and a two per cent cream applied once or twice a day to the affected areas of skin. He may also need a mildly potent corticosteroid to ease the inflammation and possibly antibiotics if there is a bacterial infection.