Sometimes the whole skin becomes red and scaly (see Fig. 5.13). The disorders that can cause this are listed in Table 6.4. The best clue to the underlying cause is a history of a previous skin disease. Sometimes the histology is helpful but often it is non-specific. ‘Erythroderma’ is the term used when the skin is red with little or no scaling, while the term ‘exfoliative dermatitis’ is preferred if scaling predominates.
Most patients have lymphadenopathy, and many have hepatomegaly as well. If the condition becomes chronic, tightness of the facial skin leads to ectropion, scalp and body hair may be lost, and the nails become thickened and may be shed too. Temperature regula-tion is impaired and heat loss through the skin usually makes the patient feel cold and shiver. Oedema, high output cardiac failure, tachycardia, anaemia, failure to sweat and dehydration can occur. Treatment is that of the underlying condition.