Dermatology Pruritus Scratch marks generally present: Jaundice Renal failure Localised: Dermatitis or eczema Hair follicle infections Folliculitis Superficial inflammation of the hair follicles. Mostly are due to S. aureus Furuncles Deeper infection of the hair follicles Carbuncles When a furuncle spreads and involves a number of hair follicles. Distribution Can occur anywhere. Most common sites: Buttocks Neck Anogenital area Features Very painful Systemic symptoms Deep lesions heal by rupturing and exudating pus. Often leave scars. Blisters Viral E.g. HSV Distinctive morphology: Small grouped vesicles on an erythematous -> herpetiform Bullous Pemphington Autoimmune blistering Usually affects older people Widespread and tense Have a thick roof Tend to easily rupture Pemphigus Vulgaris Autoimmune disease Often younger patients More severe than the one above. Thin roofed Readily rupture Fragile epidermis Can sometimes shear with lateral pressure -> Nikolsky’s sign Almost all have oral mucosa involvement Many have mother mucosal sites: Eyes Genitals Dermatitis Herpetiform Manifestation of gluten sensitivity Pruritic papules or vesicles Favours extensor surfaces, back and buttocks Porphyria cutaneous Trada Metabolic disorders Characterised by clear or haemorrhagic tense blisters on the dorsal hands and other sun-exposed areas Hyperpigmentation Increased fascial hair Hepatic insults from hepatitis C, alcohol and haemochromatosis and the oral contraceptive pill can induce symptoms. As they decrease uroporphyrinogen decarboxylase Erythroderma Best though as the end stage of numerous skin conditions. Pustular and crusted lesions Accumulation of neutrophils Usually indicative infective causes. However, sterile pustules may form as a number of skin diseases owning to the release of chemotactic factors following an immunological reactions . A crust is a dried serum, blood pr pus that is found on the skin’s surface. May include bacterial such as staphylococcus, such as in impetigo. IMPORTANT to determine if it is a pustular lesion or a group of pustular lesions. Represents a primarily infectious process or an inflammatory dermatological process. Dermal plaques Causes by thickening of the skin that are causes by changes of the dermis or subcutaneous fat. These may be due to chronic inflammatory process or scaring sclerotic process. The pattern of involvement of the plaques, age of the patient and other clinical features should enable a diagnosis to be established. Causes: Granuloma annulare Necrobiosis lipoma Sarcoidosis Erythema nodosum Lupus erythematous Morphoea and scleroderma TB Leprosy