Taking a history
The truism that ‘there is no substitute for a good history’ is just as applicable in dermatology as in any other branch of medicine. The time needed to take a history depends on the complaint. For example, the history in a patient with hand warts can usually be completed quickly, but more time and detailed questioning are required for the patient with generalized itching.
Presenting complaint
Case history 1
An 18-year-old male bank clerk developed a scaly erythematous plaque on the left elbow (Fig. 1) 6 months before presentation. It spread to involve the other elbow and both knees, but was not itchy. He developed scaliness in the scalp and nail dystrophy. His mother once had a similar rash.
Past medical history
Patients must be asked about any previous skin disease or atopic symptoms, such as hay fever, asthma or childhood eczema. Internal medical disorders may be relevant; these can involve the skin directly or may be associated with certain skin diseases. Prescribed or self-administered drugs may also cause an eruption. Dietary history is occasionally important, e.g. in some patients with atopic eczema (p. 36), but diet is often erroneously blamed for skin disease.
Case history 2
A 29-year-old woman was referred from the department of respiratory medicine where she had recently been diagnosed as having pulmonary sarcoidosis. Three weeks previously, she had developed tender, warm erythematous nodules (Fig. 2) on the shins. She was on no medication. An incisional biopsy confirmed the clinical impression.
