Category Archives: Dermatology

Systemic Sclerosis and Morphoea (Scleroderma)

The term scleroderma means a thickening or hardening of the skin associated with an increase in its collagen content. Thickening of the skin also occurs in association with other conditions, such as porphyria or the carcinoid syndrome. In these conditions the lesion is called pseudoscleroderma. The generic term ‘scleroderma’ should not be used, as systemic sclerosis and morphoea are distinct entities. S

Cutaneous Manifestations of Systemic Diseases

The skin is frequently involved in systemic diseases. In this section, only conditions with major cutaneous manifestations that are not dealt with elsewhere are considered. CONNECTIVE-TISSUE DISEASES These systemic diseases often have cutaneous manifestations, which are described here. Systemic lupus erythematosus Photosensitivity is a presenting feature in about one-fifth of patients and may occur with a greater

Facial dermatoses/rashes

This section includes acne vulgaris and rosacea. Lupus erythematosus and photodermatoses which also cause facial rashes are discussed on p. 1021 and 1036. Acne vulgaris This chronic condition is associated with the blockage of the pilosebaceous duct and appears on areas of the skin, such as the face, chest and back, where sebaceous glands are most numerous and active. Superficial blocking of the pilosebaceous


Scabies (the itch) Scabies is a highly irritant condition occurring on the skin of an individual sensitized to the female mite of Sarcoptes scabiei or its products. MODE OF TRANSMISSION Transmission is by skin-to-skin contact with an affected individual and usually occurs in bed. Holding hands is a less common mode of spread from infested children, as warmth is necessary for the mite or acarus to remain mobile. Mos

Bullous disease

In these rare disorders, bullae form the primary lesions and these result from cleavage at various levels at or near the epidermodermal junction. There is a significant mortality associated with the diseases and the treatments. Immunopathological findings are useful in the confirmation of the diagnosis, in monitoring disease activity, and for understanding the pathogenesis. PEMPHIGUS Pemphigus is a rare disea


Dermatophytes or ringworm fungi are able to invade the keratinized tissue of the skin, nails or hair and include Epidermophyton, Microsporum or Trichophyton. The term ‘tinea’ means ‘moth-eaten’ and may be used to denote the pattern of involvement, e.g. tinea capitis. The source of the fungus may be zoophilic (animal to man), anthrophilic (human to human) or geophilic (soil to man). Scrapings

Fungal Infections

Fungal infections of the skin can be divided into those associated with yeasts such as Candida albicans and others caused by dermatophytes or ringworm fungi. CANDIDIASIS  AETIOLOGY  Use of drugs such as corticosteroids, cytotoxics, antibiotics and oral contraceptives can predispose to candidiasis. It is now a major problem in patients with AIDS. Local factors in the skin, such as maceration, may predispose to se


Plaque psoriasis Lesions are well demarcated, salmon pink in colour and are surmounted by silvery scaling that may be exaggerated by lightly traumatizing the skin with the edge of a finger-nail. The majority of patients with a plaque type of psoriasis show involvement of the skin over the extensor surfaces of the limbs such as the elbows and knees, with scattered smaller lesions on the limbs and trunk that in


Lichen planus describes a condition in which the lesions are: • Purplish in colour • Polygonal in outline • Planar or flat-topped papules The cause is unknown but some gross forms of lichen planus may occur in association with diseases in which there is a profound immunological abnormality such as myasthenia gravis with thymoma, and with graft-versushost disease. It is also seen with autoimmune chronic l

Erythematous lesions

URTICARIA The term ‘urticaria’ implies intermittent transient swelling of the skin with a loss of fluid from vessels into the extravascular space. Dermal swelling is associated with yyweals, whilst subcutaneous fluid collection is associated with brawny lesions often around the lips and orbit (angio-oedema) or the genitalia. The skin appears completely normal afterwards (within minutes or hours).