Macule: flat circumscribed lesion <1 cm in diameter, not palpable and characterized by change in colour of skin; macules can be erythematous, hypopigmented, depigmented, hyperpigmented or any other colour (eg black-purple, yellow)

Patch: flat circumscribed lesion >1 cm in diameter

Papule: raised solid lesion <1 cm in diameter

Nodule: raised solid lesion >1 cm in diameter; greatest mass below skin surface

Plaque: a flat-topped nodule >1 cm in diameter

Vesicle: clear fluid-filled lesion <1 cm in diameter

Pustule: pus or exudate-filled lesion <1 cm in diameter

Bulla: clear fluid-filled lesion >1 cm in diameter

Exudate: moist serum, blood or pus from an erosion, bulla or pustule

Lichenification: grouped flat-topped papules associated with exaggerated skin markings, diffuse thickening and hyperpigmentation

Excoriations: linear erosions caused by loss of epidermis and superficial dermis due to scratching

Erosions: loss of superficial epidermis causing superficial depression

Fissures: linear wedge shaped cracks in the epidermis extending down to the dermis and narrowing at the base

Ulceration: full thickness loss of epidermis, some dermis and subcutaneous fat

Scaling: dry flaky surface with normal or abnormal keratin from shed epidermal cells

Crusting: dried exudates (serum, blood, pus, damaged epithelial cells)

Scarring: atrophic (thinning or loss of epidemis and/or dermis); hypertrophic

Maceration: appearance of surface softening due to constant moistness

Linear

Grouped

Circinate

Annular

Reticulate

Serpiginous

Geographical

Segmental

Zosteriform or dermatomal

Symmetrical

Peripheral or central

Limbs (extensor; flexural)

Evaluation of general skin appearance: colour; texture; dryness; hydration; odour

Site predilection: sun-exposed; acral; flexures; extensor surfaces

If generalized, whether symmetrical (if so, whether central or peripheral) or not

Shape of skin lesions: round, oval, annular, iris shaped, umbilicated

Arrangement: isolated, grouped (linear, annular, serpiginous)

Involvement of scalp, palms, soles, ears, sub-mammary and interdigital areas, hair-bearing areas (axillae, groins); perianal skin

Involvement of skin appendages: hair; nails

Mucosal involvement: oral cavity; lips; conjunctivae; nasal cavity

Red: hyperaemia; telangiectasia; petechiae; purpura; ecchymosis

Blue: haematoma; dermal melanin; cyanosis

Brown: dermal and epidermal melanin; haemosiderin

Yellow: carotenoids; bile

Grey-black: epidermal melanin; foreign bodies; heavy metals; tar

White: depigmentation (loss of melanin)

Scarlet fever: sudden onset of sore throat, headache, high fever and chills, malaise, anorexia and nausea followed 1–2 days later by a generalised erythematous pinhead rash, initially on the neck, chest, axillae and abdomen, with sand-paper like texture (due to tiny papules) and sparing of the palms and soles; flushed cheeks with circumoral pallor and strawberry tongue (glossitis, with dilated papillae); pharyngeal exudate, punctate petechiae of the palate and uvula, cervical lymphadenopathy; streaks of petechiae along the axillary skin folds (Pastia lines)

Drug eruption: morbilliform skin rash, eosinophilia, and systemic symptoms including high fever and organ involvement (DRESS refers to a drug reaction with eosinophilia and systemic symptoms, associated with a triad of fever, skin rash and internal organ involvement, including hepatitis, nephritis, pneumonitis, myocarditis, thyroiditis; there is a two to three-week period between initial exposure to the drug and onset of the reaction)

Toxic shock syndrome

Staphylococcal scalded skin syndrome (prodrome of fever, malaise and sore throat; skin tenderness and erythema, initially peri-orificial in the face, and in the neck, axillae and groins, with rapid progression over 24–48 h to diffuse erythroderma, accentuated in flexural areas; peri-oral erythema; large flaccid bullae may develop in the flexures and around orifices; diffuse desquamation leads to peri-oral, peri-nasal and peri-ocular crusting; resolution without scarring takes place within 2 weeks); early toxic epidermal necrolysis

Erythroderma (red and scaly) secondary to drugs, eczema, psoriasis or T –cell lymphoma; may be idiopathic

Scombrotoxicity

Meningococcaemia (onset with prodrome of fever, headache and upper respiratory symptoms; a maculopapular rash may precede petechiae; the non-blanching petechial or purpuric rash may initially be found only in warm areas, such as groins and axillae; in patients with darker skin, the soles of the feet and palms of the hands should be examined; the petechiae may have angular edges and a greyish interior; acrocyanosis of the ears, nose, lips, legs and genitalia; cold hands and feet; leg pain; confluent ecchmyoses with central necrosis can progress to gangrene)

Gonococcaemia: haemorrhagic papules and pustules that develop a crust and become necrotic

Henoch Schonlein purpura

Staphylococcal endocarditis

Idiopathic thrombocytopenic purpura

Overwheming pneumococcal sepsis (in asplenic individuals)

Disseminated intravascular coagulation (purpurafulminans)

Leptospirosis

Enteroviral infection

Viral haemorrhagic fevers (Ebola, Marburg)

Yellow fever; dengue fever

Toxic shock syndrome

Rat bite fevers: spirillum minus; streptobacillusmoniliformis

Capnophagacanimorsus (DF-2) infection: in asplenic individuals, especially after dog bites

Vitamin C deficiency (scurvy) (peri-follicular purpura; lower limb eccymoses; haemorrhagic gingivitis)

Catastrophic anti-phospholipid antibody syndrome

Viral infections: rubella (mild prodrome; pink macular rash appearing on the face and spreading to the trunk and limbs,becoming confluent; red macules or petechiae on soft palate; post-auricular, posterior cervical and suboccipital lymphadenopathy); measles (prodromal 3 Cs of cough, coryza and conjunctivitis with photophobia; generalised erythematous maculopapular rash, starting on the backs of the ears and spreading to the head and neck and rest of the body, turning brown before disappearance; Koplik spots (1 mm white spots, resembling grains of sand, on an erythematous background, in the buccal mucosa in the lower premolar region)); enteroviruses; acute HIV infection; uncomplicated dengue; aminopenicillin therapy in the presence of Epstein-Barr virus

Rickettsial infections

Mycoplasma and chlamydial infections

Bacterial/spirochaetal infections: secondary syphilis; leptospirosis; meningococcaemia

Acute retroviral syndrome (HIV)

Erythema nodosum

Streptococcal infections

Sarcoidosis

Inflammatory bowel disease

Disseminated fungal infection

Disseminated tuberculosis/atypical mycobacteria

Sweet’s syndrome

Pseudomonas aeruginosa-echythmagangrenosum

Lyme disease

Typhoid

Varicella (successive crops of erythematous macules, papules, clear vesicles placed eccentrically on an erythematous base-dew drop on rose petal appearance, pustules, followed by central umbilication, erosion and crusting evolving over 12–24 h; lesions are seen in different stages of evolution; usually no prodrome in children, or a prodrome of nausea, anorexia, myalgia and headache in adults; starts on trunk-centripetal distribution-and spreads to face and limbs-centrifugal spread, sparing palms and soles; reinfection or a second clinical attack virtually unheard of)

Toxic epidermal necrolysis

Pemphigus vulgaris

Erythema multiforme major (Stevens-Johnson syndrome: fever, sore throat, flaccid bullae, painful ulcers in the mouth, lips, anal and genital regions, and keratoconjunctivitis)

Bullous pemphigoid

Drug eruptions

Disseminated herpes simplex (eczema herpeticum: in patients with atopic dermatitis and other widespread skin diseases, resulting from auto-inoculation usually from labial HSV or hetero-inoculation from an infected contact; rapidly spreading blistering eruption evolving into large erosions and ulcers, associated with fever)

Bullous erythema multiforme

Staphylococcal infections

Zoster (unilateral painful eruption of grouped vesicles along a dermatome, with hyperaesthesia and occasionally regional lymph node enlargement)

Hand-foot-and mouth disease

Contact dermatitis

Bacterial folliculitis

Generalisedpustular psoriasis: small, sterile pruritic non-follicular pustules within large areas of erythema; oedema of the hands and feet (de novo or complicating atypical, acral or flexural disease)

Acute generalized erythematous pustulosis

Shaving, plucking or waxing hair

Occlusion or maceration of skin

Topical steroid therapy

Atopic dermatitis

Diabetes mellitus

Inadequately chlorinated hot tubs, whirlpools and swimming pools

Systemic symptoms

Fever

Altered mental state

Co-morbidity: immunocompromised

Large area of skin involvement

Mucosal or ocular involvement

Central distribution: drug eruption; pityriasisrosea; viral infection

Peripheral distribution: scabies; atopic dermatitis

Central distribution: viral exanthema (measles, rubella, rubeola, roseola- circular to elliptical rose-red macules or papules involving trunk, occasionally surrounded by a white halo, erythema infectiosum-slapped cheeks, with bright red erythema, infectious mononucleosis, enteroviral, adenoviral and arboviral infections); drug reaction; Kawasaki disease

Peripheral distribution: Stevens-Johnson syndrome; erythema multiforme; early meningococcaemia; early toxic shock syndrome; secondary syphilis; Lyme disease

Rubella

Parvovirus B19 (slapped cheek syndrome; viral prodrome, slapped cheeks, peri-oral pallor, sparing of palms and soles)

Hepatitis B

Adenovirus

Echovirus

Coxsackie

Epstein-Barr virus

Senile purpura

Steroid therapy

Vitamin C deficiency

Hereditary connective tissue diseases: Ehlers-Danlos syndrome; Marfan syndrome

Mechanical: trauma, suction to skin, stasis, factitious

Anoxic-microvascular obstruction: consumption coagulopathies: DIC, TTP, haemolyticuraemic syndrome; purpurafulminans; fat embolism; myeloproliferative disease

Hypersensitivity vasculitis: Henoch-Schonleinpurpura (tetrad of purpura, abdominal pain, renal disease and arthritis or arthralgia); collagen vascular disease

Leukocytoclasticvasculitis

Infective vasculitis: meningoccal, streptococcal, gonococcal

Dysproteinemias

Angiokeratoma

Cherryangioma

Pyogenic granuloma

Kaposi’s sarcoma

Thrombocytopenia

Functional platelet disorders

Coagulopathies

Dry skin (xerosis)

Atopic dermatitis (itchy, dry erythematous scaly patches with vesicles and exudation; flexural dermatitis with lichenification, egantecubital and popliteal fossae; involvement of eyelids; cheilitis; white dermographism; recurrent conjunctivitis, keratoconus, anterior and/or posterior subcapsular cataracts; personal/family history of atopic disease; increased susceptibility to viral infections; enhanced sensivity to irritation by detergents, wool and certain chemicals)

Contact dermatitis

Drugs: statins, ACE inhibitors, opiates, barbiturates, recreational drugs, antidepressants, oral retinoids

Urticaria

Conjugated hyperbilirubinemia (cholestasis)

Scabies: linear burrows, erythematous papules, vesicles, excoriations, crusts and pustules which are symmetrical in distribution and typically involve the inter-digital web spaces, flexor aspects of the wrists, axillae and the waist, showing a predilection for warm moist areas. Thick scaly plaques characterize Norwegian or crusted scabies.

Chronic kidney disease

Biliary obstruction

Papularurticaria

Animal mites

Flea bites

Lice infestations (Pediculosis)

Iron deficiency anaemia