I have a very itchy, scaly scalp, and often have flakes of dandruff on my collar. My doctor said it might be psoriasis and gave me a treatment called Dovonex. It hasn't worked and the itching and flaking are driving me mad.
It could be psoriasis, but it might not be. Psoriasis is a skin condition that often runs in families, can cause scaly patches on elbows, knees and elsewhere, and can involve joints and nails. Scalp treatments include tar shampoos, steroid lotions such as Betnovate, and the relatively new Dovonex. Perhaps you've actually got seborrhoeic dermatitis. This makes lots of people a bit flaky. It causes dandruff, red eyes, red patches down the middle of the face and red, scaly patches in the body's crevices - armpits, groins and under breasts. It's a cross between psoriasis and eczema and is often misdiagnosed as both. As with most common skin conditions, no one has a clue what really causes it. A fungus which usually lives on the skin, P ovale, seems responsible in many cases and contributes to the itching. Treatment with Nizoral shampoo helps the scaling, though it can bounce back, especially when you're stressed.
My 15-year-old daughter has been dieting for the past year. She has undoubtedly shed her puppy fat and looks fashionably trim now. She says she's eating plenty and realises she doesn't need to lose any weight now. How can I be sure that she's not letting her dieting get out of control and sliding into anorexia?
You're right to be worried. Up to 10% of all adolescent girls in the UK are thought to have an eating disorder, and 1-2% have anorexia. On the plus side, 98% of UK adolescents are never going to be anorexic. Four factors make the diagnosis: weight that is less than 85% of ideal body weight; an intense fear of becoming overweight; distorted body image; and no periods for at least three months. If you have a good relationship with your daughter, you may be able to ask her for this information. But if she has anorexia, she may be reluctant to tell you the truth. If you suspect she is sliding towards an eating disorder, get expert help. Pointers to anorexia may be that she's exercising excessively, getting obsessed with food, feeling cold, tired and weak, and looking increasingly skinny. The specialist help will aim to treat any physical problems created by the anorexia, set targets for regaining weight, help her with relationship problems and offer therapy to work on her distorted body image. With help, half the girls with anorexia recover fully, just under half remain uncomfortable with food and have some sort of eating disorder, and one in 20 die.
It's only March and my hay fever is in full swing. Is there anything new under the sun?
March hay fever means you're probably allergic to birch pollen. Ideally, you'd avoid birches, but if you're like me and can just about tell a tree from a lamppost, forget it. Most hay fever sufferers are also allergic to grass pollen, which is easier to identify but harder to avoid. Keep bedroom windows closed as pollen counts rise, especially from mid-afternoon onwards. Ideally, move to the seaside where counts are lower. Wear wraparound sunglasses to keep pollen out of your eyes, and point ventilation vents in cars away from your face. The earlier you start your hay fever treatments, the better. Start with nose and eye drops, and build up to oral antihistamines if needs be (eg loratidine, cetirizine or fexofenadine). Nasal steroids work well if you get them up your nostrils as opposed to squirting them straight down your throat. Oral steroids are good in extreme cases such as job interviews or A-levels. Desensitisation (immunotherapy), which uses injections of increasing strengths of pollen extracts to build up immunity, works well but had a bad press due to a few fatal allergic reactions. It can be great but can only safely be given in a hospital setting - you wouldn't want to have densensitisation without a full resuscitation crew on hand.
• These answers are intended to be as accurate and full as possible, but should never be used as a substitute for visiting a doctor and seeking medical help. If you have a question for Dr Robinson, email email@example.com or write to her c/o The Health Editor, The Guardian, 119 Farringdon Road, London EC1R 3ER. She regrets that she cannot enter into personal correspondence.