Premalignant disorders in the skin are those which, if left untreated, may become skin cancers. The most important cancers with pre-cancerous states include squamous cell carcinoma (actinic keratosis; syn. solar keratosis) and melanoma (dysplastic naevus), although it is important to…
A naevus is a benign proliferation of one or more of the normal constituent cells of the skin. Naevi may be present at birth or may develop later. The commonest naevi are those containing benign collections of melanocytic naevus cells,…
Any connective tissue or appendageal element of the skin may undergo benign (and malignant) proliferation. Common non-malignant dermal growths such as dermatofibroma, lipoma and keloid are discussed in Chapter 52 (p. 114). Benign tumours of vascular and connective tissue Benign…
Skin tumours are common, and their incidence is rising in Western countries (p. 32). The treatment of skin tumours makes up a large part of current dermatological practice (p. 33). Many skin tumours of the epidermis and dermis are benign,…
Certain inherited skin disorders also have significant involvement of internal organs. The neurocutaneous disorders, the inherited diseases of connective tissue and the premature ageing syndromes are included. Neurofibromatosis von Recklinghausen’s neurofibromatosis 1 (NF1) is relatively common, affecting about 1 in…
Common skin disorders, e.g. atopic eczema or psoriasis, have a genetic component that is often subject to environmental influences. The genodermatoses differ in being single gene defects and include keratinization, blistering and neurocutaneous syndromes. The ichthyoses The ichthyoses are inherited…
Internal malignancy causes a variety of skin changes ( Table 49.1 ). Apart from direct infiltration, the mechanisms of these effects are often poorly understood. Some genetic conditions associated with malignancy include characteristic skin lesions that may arise before or…
Reactions to drugs are common and often produce an eruption. Almost any drug can result in any reaction, although some patterns are more common with certain drugs. Not all reactions are ‘allergic’ in nature. Aetiopathogenesis Drug-induced skin reactions have several…
Skin signs are seen with many internal disorders and are not uncommonly their presenting feature. The astute dermatologist can recognize undiagnosed systemic disease. Skin changes are common in pregnancy ( Chapter 69 ). Sometimes itch alone is the primary symptom.…
Vasculitis and the reactive erythemas are characterized by inflammation within or around blood vessels. This may result from a type III hypersensitivity response, with circulating immune complexes, but other mechanisms are also possible. Vasculitis Vasculitis is a disease process usually…