39. Skin rash/ eruptions Clinical skills Able to take focussed history in relation to rash/ eruptions Specifically ask about: Duration of rash/ lesions o Site of onset o Spread o Distribution Associated symptoms e.g. itch, pain Aggravating factors e.g. sunlight, heat Previous treatments PMH of psoriasis/ atopy DH including any previous treatment of current rash/ lesion FH of psoriasis/ atopy Occupation, especially if exposure to chemical irritants SH including pets Able to perform examination of skin and related structures Skin Examine all the skin, hair and nails Regarding rash/ lesions, consider: o Distribution – flexures/ extensors, symmetrical? o Are there grouped lesions? o Are there crops of lesions? o Are the lesions monomorphic (taking all one form) or polymorphic? o Is there evidence of Kobners phenomenon (skin lesions which develop at site of injury)? o Pattern of lesions – ring/ linear/ targetoid (rounded lesion that is circumferentially rimmed by >2 distinct densities or colours)? Examine genitalia and mouth also for any lesions Able to make clinical diagnosis of common skin rash/ eruptions Symmetrical flexural distribution → atopic eczema Symmetrical extensor surface distribution → psoriasis Distribution at site of contact with jewellery or cosmetics → allergic contact dermatitis Distribution in areas exposed to sun e.g. back of hands, face, neck → photosensitivity Grouped lesions → herpes virus Ring pattern (active edge with healing centre) → fungal infection Linear pattern → Kobner’s phenomenon at sites of injury in psoriasis, lichen planus, plane warts and vitiligo Targetoid pattern → erythema multiforme Ring shaped lesions differentials Basal cell cancer - forms a ‘rodent ulcer’ i.e. pearly papule with central ulcer Tinea (ringworm) Granuloma annulare (benign, chronic inflammatory skin condition) – 1cm ring lesions seen on hands Erythema multiforme – targetoid lesions commonly on extensor limb surfaces Rarely, leprosy Brown pigmented lesions differentials Sun-related freckles Lentigos – persistent brown macules, often larger than freckles Café-au-lait spots – faint brown macules, if >5 consider neurofibromatosis Sebarrhoeic keratoses/ warts – benign greasy brown warty lesions usually on the face, back and chest, very common in the elderly Malignant melanoma Chloasma (melasma) – brown patches on the face, related to pregnancy or Pill use, may respond to topical azelaic acid Systemic diseases e.g. o Addisons causing hyperpigmentation in the palmar creases, oral mucosa and scars o Haemochromotosis o Porphyria cutanea tarda (+skin fragility and blisters) Round, oval or coin-shaped (discoid) lesions differentials Bowen’s disease – squamous cell carcinoma in situ, causing a well demarcated erythematous plaque with an irregular border and surface crusting or scaling Discoid eczema – itchy/crusted/scaly eczema that is worsened by heat Psoriasis Pityriasis rosea – oval red lesions with scaly edge e.g. on trunk Erythema chronicum migrans Impetigo – well-defined red patches, covered with honey-coloured crust Linear lesions differentials Kobner phenomenon – seen in psoriasis, lichen planus Dermatitis artefacta – lesions induced by patient, may be linear or bizarre-shaped Herpes zoster – polymorphous vesicles/pustules in a dermatomal distribution Scabies burrows – mite is visible as a speck just above a red linear lesion Subcutaneous nodules differentials Rheumatoid nodule Rheumatic fever Polyarteritis nodosa (PAN) Xanthelasma Tuberous sclerosis Neurofibroma Sarcoid Granuloma annulare Dermatology definitions Alopecia Hair loss Atopy/ atopic Prone to allergic eczema, asthma or rhinitis. Typically affects city-based children Atrophy Thinning and loss of skin substance Bulla Blister >0.5cm in diameter Vesicle Blister <0.5cm in diameter Crust Dried brownish exudates Erythema Reddening of the skin which blanches on pressure Purpura Purplish lesion resulting from free RBCs in the skin – does not blanch on pressure, may be nodular in vasculitis Excoriation A scratch which has broken the surface of the skin Pustule Well-defined pus filled lesion Macule Defined, flat area of altered pigmentation. Large macules are known as patches Nodule Solid lump >0.5cm in diameter, subcutaneous or intradermal Papule Raised, well-defined lesion <0.5cm in diameter Weals/ Transient pale papules with pink margins (known as hives) urticaria Scale Fragment of dry skin Ulcer Loss of epidermis and dermis which heals with scarring Erosion Superficial break in epidermal layer which heals without scarring Underpinning sciences Basic medical sciences Structure and functions of the skin The skin consists of two layers – the epidermis and dermis Beneath the dermis is a layer of subcutaneous fat known as the hypodermis, and beneath this layer lies muscle Epidermis Relatively thin outer layer of the skin Most of the cells are keratinocytes, which originate from stem cells in the deepest basal layer and migrate upwards to the surface of the skin undergoing maturation. Once keratinocytes reach the skin surface, they are shed and replaced by newer cells Divided into five layers: Layer of epidermis Stratum corneum Contents Composed of 10-30 layers of corneocytes (final stage of keratinocyte differentiation); palms and soles have the most layers Function Relatively waterproof When undamaged, prevents most bacteria, viruses, and other foreign substances from entering the body Stratum lucidum Translucent layer of dead skin cells that is only found in thick skin Helps reduce friction and shear forces between stratum corneum and granulosum in areas of thick skin Stratum granulosum Keratinocytes have lost their nuclei and become granular in appearance Keratin proteins and water-proofing lipids are produced and organised Stratum spinosum Contains columnar stem cells in the first stage of differentiation Langerhans cells are most prominent in this layer Stratum basale/ germinativum Composed of one row of undifferentiated columnar stem cells that divide very frequently Attached to the basement membrane by hemidesmosomes Melanocytes are also present in this layer Stem cells start to synthesise keratin Langerhans cells are part of the skins immune system; they take up microbial antigens and become antigen-presenting cells to T cells. Also have a role in skin allergies Half of the stem cells differentiate and move to the next layer to begin maturation. The other half stay in the basal layer and divide to replenish the layer Melanocytes produce the pigment melanin which contribute to skin colour and filter out UV rays from sunlight Dermis A thick layer of fibrous and elastic tissue made mostly of collagen, elastin and fibrillin – giving the skin flexibility and strength Contains nerve endings, sweat glands, sebaceous glands, hair follicles and blood vessels o Nerve endings sense pain, tough, pressure and temperature – some areas contain more nerve endings that other e.g. fingertips and toes o Sweat glands produce sweat in response to heat and stress – there are specialised apocrine sweat glands in the armpits and genital regions that secrete a thick oily sweat which causes body odour if digested by skin bacteria in those areas o Sebaceous glands secrete sebum into hair follicles – this keeps the skin moist and soft and acts as a barrier against foreign substances o Hair follicles produce the various types of hair found throughout the body, which is involved in regulating body temperature, providing protection from injury and enhancing sensation o Blood vessels of the dermis provide nutrients to the skin and help regulate body temperature via vasodilation/ vasoconstriction Subcutaneous fat layer Fat layer varies in thickness around the body Helps insulate the body, provides protective padding and serves as an energy storage area Index conditions EXANTHEMA SUBITUM (roseala infantum/ sixth disease) Epidemiology Most common in infants aged 6-18 months Aetiology Infection with human herpes virus 6 (HHV 6) Clinical features Incubation period of 10-15 days Pyrexia Lasts for 3-4 days Uncommonly causes febrile convulsions Macular exanthem (transient rash) Rose pink in colour Begins with pyrexia Initially involves the trunk, may spread to face and extremities Lasts for 2 days without desquamation or pigmentation Mild pharyngitis and lymphadenopathy Management Mild and self-limiting condition; no treatment recommended MENINGOCOCCAL DISEASE Causative organism Neisseria meningitidis Symptoms General – in meningitis/ sepsis/ both Fever Lethargy Poor feeding/vomiting Irritability Drowsiness Loss of consciousness Seizures Specific to meningitis Headache Photophobia In infants under 18 months, late signs include: bulging fontanelle, neck stiffness and arched back Specific to sepsis Non-blanching pupuric rash Signs Pyrexial Non-blanching purpuric rash may be present/ may develop Investigations Management Positive Brudzinski’s sign i.e. flexion of the neck with the child supine causes pain and resultant flexion of the knees and hips Positive Kernig’s sign i.e. when the child is lying supine with the hips and knees flexed, there is pain on extension of the knee Signs of shock – capillary refill time over 2 seconds, tachycardia, tachypnoea, pale, cold extremities Focal neurological signs if meningitis Altered conscious level – poor AVPU score Papilloedema on funduscopy (rare) FBC and CRP– shows raised white cell count and raised CRP Coagulation screen – to see if there are lowered platelets, elevated prothrombin time and elevated activated partial thromboplastin time (aPPT), which would indicate DIC was occurring U&Es, LFTs BM Arterial blood gas Lumbar puncture + culture of CSF unless contraindicated Blood cultures Rapid antigen test for meninigitis organisms; can be done on blood, CSF or urine Cultures from throat swab and scrapings of purpuric lesion if present Consider CT/MRI head and EEG Resuscitation: ABCDE Drug treatment In primary care: IM benzylpenicillin In hospital: cefotaxime or ceftriaxone (+ ampicillin in neonates to cover possibility of Listeria monocytogenes) for 7 days in sepsis alone or 10-14 days with meningitis Dexamethasone (after the neonatal period) administered with antibiotics reduces the risk of deafness Anticoagulants are frequently given if there is DIC although it is not known whether this improves outcome Other management IV fluids + fluid bolus if shocked - unless there is evidence of raised intracranial pressure Dialysis or haemofiltration is usually required for fulminant (i.e. rapidly spreading) meningococcal sepsis DRUG ERUPTIONS Clear history of onset and duration of rash is essential Record all drugs taken including herbal remedies Stop likely offenders immediately If clinical diagnosis is in doubt, prick test or skin biopsy may be useful Some advocate re-challenge with the suspected drug once the patient has recovered; not often used in practice due to risk of erythoderma/ anaphylaxis and often against patient wishes Most are self-limiting; erythema multiforme and toxic epidermal necrolysis require referral to a specialist Type of reaction Muculopapular Clinical features Management Generalised erythematous macules and papules particularly affecting the trunk +/fever and eosinophilia Typically develops within 2 weeks after the onset of drug therapy Most common type of drug eruption Causative drugs: penicillins, cephalosporins, anti-epileptics Wheals +/- angioedema/ anaphylaxis Rapid onset after taking drug Can result from immunological and nonimmunological mechanisms Causative drugs: morphine, codeine (direct mast cell degranulation); penicillins, cephalosporins (IgE responses); NSAIDs; ACE-inhibitors Prompt antihistamine +/- IV hydrocortisone/ IM adrenaline if anaphylaxis Widespread erythema and dermatitis + erythoderma (scaling) Causative drugs: sulphonamides, allopurinol, carbamazepine, gold Emollients if dryness Short course of topical steroids if severe itch Target lesions and polymorphic erythema + blistering mucosae (conjunctivae, oral, labial, genital) Causative drugs: sulphonamides, anticonvulsants (phenytoin, barbiturates) Refer to dermatologist Management options include no treatment or use of steroids An extreme end of the erythema multiforme spectrum Widespread erythema and epidermal necrosis with loss of large sheets of epidermis Mucosae severely affected Increased risk in HIV patients Mortality 30% - death usually due to infection or ARDS Causative drugs: sulfomamides, anticonvulsants (phenytoin, phenobarbitol, carbamazepine, valproic acid), penicillins, allopurinol, NSAIDs Admit to hospital and manage in a dermatology or burns unit Short term dexamethasone pulse therapy IVIG Utricaria Exfoliative dermatitis Erythema multiforme major (StevenJohnsons syndrome) Toxic epidermal necrolysis Self-limiting, usually no treatment required Regular emollients if dryness or itch Lichenoid Well-defined purple papules distributed symmetrically over trunk and limbs Can be severely pruritic May be scaly Oral lesions uncommon Causative drugs: beta blockers, thiazides, gold, antimalarials Short course of topical steroids if severe itch LICHEN PLANUS Clinical features Lesions commonly seen on flexor aspects of wrists; forearms; ankles and legs Lesions are purple, polyangular, planar (flat-topped) papules Associated pruritis White lacy markings known as Wickham’s striae are also seen Lesions often arise at sites of trauma Other features: Scarring alopecia on the scalp Longitudinal ridges on nails Lacy white areas on inner cheeks of mouth and tongue Genital lesions Management Usually persists for 6-18 months First line: Moderate to potent topical steroids e.g. betamethasone diproprionate 0.25%, fluocinonide 0.05% +/- topical antifungals (used especially in oral disease e.g. fluticasone spray) Severe disease: systemic steroids PHOTOSENSITIVITY Photosensitivity = skin conditions triggered by light i.e. solar urticaria, polymorphic light eruption, poryphyria cutanea tarda and SLE. Can occur to visible light, UVA or UVB Not to be confused with photoaggravation – disorders which are worsened by light but are not due to abnormal sensitivity to light e.g. recurrent herpes labialis, rosacea Polymorphic light eruption Aetiology Thought to be an immunological reaction but the precise nature is unknown Findings are consistent with a type IV delayed hypersensitivity reaction Clinical features Common idiopathic disorder Typically affects young fair skinned women in spring Management Up to several days after light exposure, itchy red papules, vesicles and plaques develop on exposed sites Usually affects chest, arms or legs – face spared Lesions often improve throughout the summer – due to the process of ‘hardening’ and tolerance to sunlight Smoking and alcohol may trigger rash Prevention Protection from sunlight with protective clothes and sunscreen (high factor UVA and UVB sunscreen) Allow gradual exposure to sunlight to acclimatise the skin, may prevent rash occurring Treating the acute condition Potent topical steroids +/- short course of systemic steroids For severe cases: desensitisation with prophylactic light therapy before sun exposure (photohardening) with UVB phototherapy or psoralen combined with UVA (PUVA) treatment. Porphyria cutanea tarda Porphyrias are a group of inherited or acquired disorders of certain enzymes in the haem biosynthetic pathway. Haem is a component of haemoglobin and other haemoproteins Aetiology Clinical features Due to a defective liver enzyme (uroporphyrinogen decarboxylase) Type 1 PCT generally begins in adulthood after exposure to certain chemicals that increase the production of porphyrins (precursors of haem) e.g. o Alcohol o Oestrogens – from OCP, hormone replacement or liver disease o Polychlorinated aromatic hydrocarbons e.g. in pesticides o Iron overload – due to excessive intake, viral infections esp hep C, chronic blood disorders such as thalassamia or haemochromotosis Type 2 PCT is familial and associated with abnormal genetic variants of uroporphyrinogen decarboxylase, generally onsets at a younger age Photosensitivity due to ↑poryphyrins in the skin: Increasingly fragile skin in areas exposed to sun e.g. back of skin and forearms Sores and erosions following minor injuries Blisters – vesicles and bullae; milia arising as blisters heal Hyperpigmentation Occasionally, hardening of skin (sclerodermoid skin) Alopecia Dark urine Investigations Diagnostic: Skin biopsy Examination of the urine with a Wood's lamp: may reveal coral pink fluorescence due to excessive porphyrins 24 hour urine porphyrin profile: elevated total porphryins Other tests: FBC and iron studies – ↑iron in 30% of patients, should prompt studies for haemochromotosis LFTs – may be deranged Fasting blood sugar - ↑incidence of associated diabetes Antinuclear antibodies - ↑incidence of associated SLE Viral hepatitis studies – PCT may be associated with hep C Management Avoid alcohol, oestrogens, iron and pesticides Sun-cream and cover up when outside Phlebotomy if ↑iron – 500ml every 1-2 weeks until iron drops, may then be required yearly Antimalarials e.g. low-dose chloroquine or hydroxychloroquine may be recommended, but must be used cautiously - makes the porphyrins more soluble so more are excreted in the urine Autologous red cell transfusion – patient’s blood cells are washed of plasma to remove circulating porphyrins and returned to the body Treat Hep C if present Solar urticaria = rare form of urticaria that occurs in response to sunlight or artificial light sourse emitting UV radiation. May be due to an antibody-antigen reaction, causing allergic reaction and urticaria Epidemiology Rare M=F Mean age of onset 35 years Clinical features Urticarial rash when exposed to sunlight/ UV radiation – may last minutes – hours If large areas of the body are affected, the loss of fluid into the skin may result in light-headedness, headache, nausea and vomiting Investigations Phototests to detect abnormal sensitivity to UVB radiation Management Avoid or minimise sun exposure Oral antihistamines may reduce urticaria but rarely prevent it altogether Severe reactions: phototherapy or photochemotherapy may be considered – desensitises patients to UV radiation but short-lived and repeat treatment often required ECZEMA= dermatitis i.e. inflammation of the dermis Classification Atopic eczema – common in children, seen in many places on the body as opposed to specific site in contact dermatitis Contact dermatitis – causes 70% of eczema, due to contact with a specific irritant/ allergen Seborrhaeic dermatitis – mainly affects the scalp (dandruff), nasolabial folds, cheeks and flexures in adults, can occur as ‘cradle cap’ in neonates Xerotic eczema – dry, itchy and cracked skin, commonly in older people in winter Venous eczema – occurs where there is impaired circulation or varicose veins, most commonly in the ankle area Atopic eczema Causes Clinical features Multifactorial Genetic: family history is common. Due to overactivity of Th2 lymphocytes, stimulating IgE production Infection: staphs can colonise eczema lesions and toxins act as a superantigen Allergens: house dust mites and animals are common allergens Diet: food allergies e.g. eggs, dairy products may exacerbate eczema Pruritis Redness and scaling of skin May have widespread of localised blisters Commonly affected areas: flexural surfaces of joints, face, groin Children may also have rhinitis, asthma, hayfever, food allergies Williams diagnostic criteria for atopic eczema – child must have itchy skin/ scratching + at least 3 of: Onset before 2 years History of skin crease involvement History of generally dry skin Personal history of other atopy or atopy in 1st degree relative Flexural dermatitis or involvement of cheeks/forehead and outer side of limbs if <4 years old Management Emollients Should be used liberally 2x per day even if eczema not active Greasy emollients e.g. epaderm in severe eczema Less greasy e.g. E45, diprobase OK in moderate eczema Bath emollients such as Oilatum may be useful Topical steroids for active sites Face, flexures and groin: 1% hydrocortisone/ 0.05% clobetasone (Eumavate) if more potent steroids needed (<1 week on face) Elsewhere: higher potency 0.1% betamethasone (Betnovate)/ clobetasol (Dermovate) is extremely potent, only for use on thick skin Haelan tape (fludroxycortide) is good at healing fissured digits Topical immunomodulators – if topical steroids cannot be used/ have failed to work E.g. tacrolimus, pimecrolimus Antihistamines – may be used to prevent itching during a flare-up Tar bandages containing itchthammol paste are used in lichenified eczema (skin changes in response to repeated scratching) If systemic treatments are required to control eczema: consider ciclosporing + get help from dermatologist Oral antibiotics if there are broken areas of skin – commonly Staph infections therefore use flucloxacillin Differentials Psoriasis – tends to occur on extensor rather than flexor surfaces Urticaria – can look similar but there are usually raised red wheals as opposed to flaking CONTACT DERMATITIS Pathophysiology Can be irritant or allergic Allergic contact dermatitis is a Type IV hypersensitivity reaction Causative agents Irritants Detergents Soaps Oils Solvents Allergens Nickel – in jewellery, watches, coins, keys Chromates – in cement, leather Lanolin – in creams, cosmetics Rubber - foam in furniture Plants (primulas) Topical antibiotics, antihistamines or anaesthetics Clinical features Investigations Pruritis Redness and scaling of skin Usually a sharp cut-off where contact ends but secondary spread is common in allergic dermatitis due to auto-sensitisation Hands most commonly affected in irritant dermatitis – weeping and dry fissuring may occur Irritant dermatitis often diagnosed on clinical grounds Allergic dermatitis: patch testing (controlled exposure to common allergens) – check for reaction 48 hours later Management Remove contact with irritant/ allergen Prevention: Emollient creams, soap substitutes if necessary, wearing gloves if exposed to causative agent Acute flare-ups: low potency topical steroids e.g. hydrocortisone, alcometasone diproprionate (aclovate) Moderate-severe: topical tacrolimus (immunosuppressant) Severe allergic dermatitis: systemic glucocorticoids/ immunomodulators such as azathioprine may rarely be needed PSORIASIS = chronic inflammatory skin condition Classification Plaque/ discoid psoriasis – most common type, plaques have a slivery-white scaly appearance Guttate psoriasis – eruption of small salmon-pink papules, 1-10mm in diameter, usually with a fine scale. URTI with group A Strep e.g. Strep. pyogenes usually precedes the eruption by 2-3 weeks Pustular psoriasis – uncommon, widespread pustules occur on an erythematous background. May have concurrent fever and toxicity with ↑WCC Plaque/ discoid psoriasis Epidemiology Affects 2% of Caucasians Peak incidence in the 20s and 50s Pathology Multifactorial Triggers Symptoms Triggers Stress Skin infections esp. Streptococcus Skin trauma (Kobner phenomenon) Drugs – lithium, beta blockers, antimalarials Alcohol Obesity Smoking Climate Signs Inflammatory infiltration of epidermis by T cells – psoriasis is commonly precede by a Strep infection, which initially activates T cells Epidermal hyperplasia and improper cell maturation Familial - 30% have a family member with psoriasis Commonly affects extensor surface of knees and elbows, scalp, sacrum, intergluteal clefts and penis Tends to following a waxing and waning course related to exposure to triggers Skin lesions Symmetrical well-defined red oedematous plaques with silvery scale on extensor surfaces Lesions frequently present in flexures also but these are non-scaly Nail changes (occur in 50%) Pitting Oncholysis (separation from nail bed) Thickening Subungual hyperkeratosis ‘pepper pot nail pitting’ ‘grease-spots’ underneath nails Ocular features – tend to occur after skin symptoms have developed Tearing and redness of eyes due to conjunctivitis/ blepharitis Other signs Aubitz sign – pinpoint bleeding on scale removal Kobner’s phenomenon – linear lesions at sites of injury Systemic features 7% develop a seronegative arthropathy (5 types – mono/oligomonoarthritis, psoriatic spondylitis, asymmetrical polyarthritis, arthritis mutilans, rheumatoid-like polyarthritis Management Education + remove triggers Topical drugs – mainstay of treatment for mild disease First line: Combined vitamin D analogue calcipotriol + betamethasone cream 0.05% (Dovobet) applied once daily Dithranol – must be washed off 30 mins after application, start at 0.1% and consider 0.25-1%. SEs: burning and staining, avoid use in flexures/ on face Tar may be used but messy Tacalcitol (vitamin D analogue) may be used once per day for up to two 12 week courses per year For flexural disease: Trimovate (topical steroid + antibiotic + antifungal) Moderate-severe psoriasis – refer to a dermatologist Goeckerman therapy – combination of coal tar applied to skin and psoralen+UVA (PUVA) artificial radiation TNF inhibitors: Etanercept/ adalimumab Immunosuppression with methotrexate or ciclosporin may be necessary TINEA CORPORIS = dermatophyte (ringworm) fungal infection on the body Risk factors for infection Living in humid conditions Wearing constrictive clothing Participating in close contact sports e.g. rugby Immunosuppresion e.g. HIV or taking immunosuppressants Clinical features Round scaly itchy lesions Edges of lesion are more inflamed than centre Investigations Skin swabs – microscopy +/- culture Management First line: Topical antifungals at least twice a day for 2 weeks e.g. clotrimazole If several lesions/ patient is immunocompromised: oral antifungals e.g. terbanifine, itraconazole BLISTERS Causes of blisters Widespread blisters Eczema Dermatitis hepetiformis Chickenpox Erythema multiforme Bullous pemphigoid Pemphigus blisters Drug eruptions Locaslised blisters Eczema Psoriasis Impetigo Herpes simplex Dermatitis hepetiformis = autoimmune blistering skin manifestation of Coeliac’s disease Clinical Itchy bullous rash features Characteristically affects extensor surfaces – scalp, buttocks, elbows, knees +/- symptoms of Coeliac disease Investigations Skin biopsy Confirm celiac disease via autoantibody testing: IgA anti-tissue transglutaminase or IgA endomysial antibodies Management Gluten-free diet Dapsone (sulphone antibiotic)/ systemic steroids may be required to reduce itch initially Chicken pox Cause Clinical features Varicella zoster virus infection, airborne spread by respiratory droplets Management Complications Fever Rash – begins initially as papules and develops vesicles. The rash typically starts on the head and trunk and progresses to the peripheries – as opposed to smallpox, which tend to start on peripheries. Lesions may occur on the palate Pruritus Pustules (lumps filled with pus and necrotic fluid, as in acne) and crusting may develop Rash has usually gone within one week – new lesions appearing after 1days suggest defective cellular immunity Other symptoms: myalgia (muscle pain), malaise, anorexia, vomiting, sore throat, sore ears Usually no treatment required Paracetamol to ease symptoms Aciclovir for severe chickenpox or in immunocompromised children Secondary bacterial skin or lower respiratory tract infection Commonly with staphylococci or group A streptococcus Can lead to further complications such as toxic shock syndrome or necrotising fasciitits Encephalitis Usually occurs early during the illness Prognosis is better than encephalitis caused by HSV Cerebillitis is characteristic – child develops ataxia and cerebellar signs Usually resolves within one month Purpura fulminans Occurs as a consequence of vasculitis in the skin and subcutaneous tissues May rarely occur after VZV due to production of antiviral antibodies which cross-react and inactivate coagulation factor protein S (more common after meningococcal sepsis, causes the dark areas of rash seen in meningococcal sepsis) Cutaneous haemorrhage and necrosis, low blood pressure, fever and DIC occur – the condition can be life-threatening In immunocompromised children: Lesions can become haemorrhagic Pneumonitis may occur Infection can become progressive and disseminated DIC can occur Mortality is up to 20% Bullous pemphigoid = a rare, autoimmune skin disorder causing supepidermal blistering Pathogenesis Autoantigens against type XVII collagen which forms the junction between epidermis and basement membrane of the dermis Epidemiology Incidence 4.28 per 100,000 person years in the UK Most common in >70s M=F Triggers Symptoms Investigations Management Lichen planus, psoriasis or any other chronic inflammatory skin disease may precede development of bullous pemphigoid Pruruitis may appear weeks-months before skin lesions Blisters/ bullae typically in skin flexures Skin may be normal/ erythematous Mucous membranes involved in ¼ patients Gold standard: Skin biopsy followed by direct immunofluorescence Indirect immunofluourescence using fluid aspirated from a blister may also be used Histology reveals a supepidermal blister with inflammatory infiltrate and eosinophilic predominance First-line in localized disease: Strong topical steroids e.g. clobetasol Prognosis For severe/ extensive disease: oral steroids +/- immunosupressives. Bisphosphonates, calcium + Vit D required in elderly patients taking steroids for more than 1 month Can persist with remissions and exacerbations for years although normally remits completely within 5 years Elderly patients are particularly at risk from steroid therapy, and complications such as secondary infection, hypertension, diabetes, osteoporosis, peptic ulcers and heart disease may occur from long term steroid use Pemphigus = a group of autoimmune disorders in which there is blistering of the epidermal layer of the skin and/or mucous membranes Three major variants: Pemphigus vulgaris – accounts for 70%, there is cutaneous blistering and oral lesions Pemphigus foliaceus - characterised by lesions which occur only in the skin Paraneoplastic pemphigus – presents in association with a tumour (may be occult) Pathophysiology IgG autoantibodies (DSG 1 and DSG3) to antigens on keratocytes, causing disruption of proteins and formation of superficial bullae in epidermal layer Epidemiology Rare: 0.68 per 100,000 person years in the UK Incidence higher in women an older age groups Triggers Drugs: penicillamine, captopril, rifampicin Burns Stress Pregnancy Vaccinations UV light Associations Other autoimmune diseases; myasthenia gravis Clinical features Skin lesions Blisters: superficial, flaccid, rupture easily, may not be intact, may be turbid Skin is normal/ erythematous and painful No pruritus Excess granulation and crusting of lesions may occur Nail lesions may occur - paronychias, nail dystrophies and subungal haematomas Mucous membranes Bullae in the oral cavity are most common: they are rarely intact, forming irregular lesions which are painful and slow to heal Lesions may occur in genitalia, conjunctiva and oesophagus Investigations Skin/ mucosal biopsy from the edge of a blister – for histological examination and immunofluorescence ELISA for autoantibodies in serum Other investigations necessary to assess if paraneoplastic pemphigus/ assess suitability for different treatments Bloods: FBC, U&Es, LFTs, BM, antinuclear antibody CXR Urinalysis for protein, blood and sugar Blood pressure Bone densitometry Management Involves compression of the immune system in 3 phases: control, consolidation, maintenance Control Mild oral disease only: topical therapy alone e.g. beclometasone spray, hydrocortisone lozenges First line for skin disease +/- oral disease: oral corticosteroids - 40-240mg prednisolone per day depending on severity for 6-8 weeks to induce remission If steroids fail: plasmapheresis to remove antibodies + cytotoxic drug e.g. axathioprine, cyclophosphamide Resistant disease: IVIG + azathioprine Once control is achieved, step-down regime is used to achieve lowest dose at which control is maintained. Azathioprine, cyclophosphamide or methotrexate may be used as maintenance to spare use of steroids Complications Prognosis Secondary infection of skin lesions Malignancies from immunosuppression especially leuakemias and lymphomas Growth impairment in children from corticosteroids Osteoporosis and adrenal sufficiency from corticosteroids Untreated pemphigus vulgaris mortality 75% Mortality greatly reduced with treatment, but many suffer long term SEs of treatment Impetigo = localised, highly contagious staphylococcal and/ or beta-haemolytic streptococcal skin infection Epidemiology Most common in Infants/ young children with pre-existing skin disease e.g. atopic eczema Clinical Lesions begin as erythematous macules which become vesicular/ bullous features blisters Ruptures of blisters causes honey-coloured crusted lesions Face, hands and neck usually affected Investigations Management Clinical/ skin swab for culture + sensitivity Mild cases: topical antibiotics e.g. mupirocin Severe cases: flucloxacillin / co-amoxiclav (easier regime so may be better in children) Affected children should not go to school until lesions are dry OCCUPATIONAL SKIN ERUPTIONS 3 types: Irritant occupational contact dermatitis – commonest type, agents have a direct toxic effect on the skin Allergic occupational contact dermatitis – type IV hypersensitivity reaction, worse prognosis than irritant Occupational contact urticaria – may be immunological (type I hypersensitivity reaction and release of IgE from mast cells) or non-immunological Common causative agents Irritant occupational contact dermatitis Alcohols Disinfectants Petroleum products Soaps Solvents Wet work Allergic occupational contact dermatitis Cobalt Chromium Cosmetics and fragrances Nickel Plants Preservatives Occupational contact dermatitis Cow dander Food and animal products Flour and grains Rubber and latex At-risk occupations Hairdressers and beauticians Health care workers Cleaners Construction workers Cooks and caterers Mechanics Metal workers Chemical/ petroleum plant operatives Agricultural workers Bakers Farmers Prevention Education for workers Limit exposure to causative agents: Gloves (cotton-liner if allergic to latex) After-work conditioning creams provided Specific treatments via GP if necessary