Mrcpch Guide Derma

MRCPCH GUIDE Derma

Erythema multiforme is a self-limiting and recurring condition that affects the skin and mucosal surfaces. The disease involves inflammatory eruptions characterised by symmetrical erythematous, oedematous or bulbous lesions of the skin and mucosal membranes. They look like target lesions with a purple or pale centre surrounded by red rings from macules that then form blisters. Involvement of the mucosal membranes includes debilitating stomatitis and conjunctivitis. Children may suffer from a persistent fever, malaise, photophobia and arthralgia. Causes of erythema multiforme are multiple, but important ones to consider include herpes simples virus, Mycoplasma and orf virus. Bacterial causes include Streptococcus, Yersinia enterocolitica, Mycobacteriumtuberculosis and Salmonella typhi/paratyphi. Systemic lupus erythematosus, polyarteritis nodosa and collagen vascular diseases are all autoimmune disorders. Histoplasmosis, carcinoma, lymphomas and leukaemias may be associated oncological factors. Important drugs to consider include sulphonamide, penicillin, barbiturate, sulphonylurea, salicylate, phenytoin, L-dopa and chlorpropamide. Many suspected etiologic factors have been reported to cause EM. Infections: Bacterial (including Bacille Calmette-Guérin (BCG) vaccination, hemolytic streptococci, legionellosis, leprosy, Neisseria meningitidis, Mycobacterium, pneumococcus, Salmonella species, Staphylococcus species, tuberculosis, Mycoplasma pneumoniae),Chlamydial, Fungal Parasitic (Trichomonas species, Toxoplasma gondii), Viral (especially herpes simplex). Drugs: Antibiotics (including, sulfonamides), anticonvulsants, aspirin, antituberculoids and many others. Physical factors - Radiotherapy, cold, sunlight Others - Collagen diseases, vasculitides, non-Hodgkin lymphoma, leukaemia, multiple myeloma, myeloid metaplasia, polycythemia EM minor is regarded as being triggered by HSV in nearly 100% of cases. A herpetic etiology also accounts for 55% of cases of EM major. Among the other infections, Mycoplasma infection appears to be a common cause. If recurrent, the possibility of IgG2 subclass deficiency should be considered.

There are two clinical alternatives that may present as erythema multiforme. There is mild erythema multiforme that presents with symmetrical target lesions that are non-pruritic and may be bulbous in nature and resolve after 4–6 weeks. Severe erythema multiforme may, however, present as Stevens–Johnson syndrome whereby a severe erythema multiforme rash appears with bullae of the mouth, anogenital region and conjunctivae. Death occurs in 5–20% of cases. Systemic effects include polyarthritis, pneumonia and severe fluid and electrolyte imbalance. Treatment options include

mouthwashes, antibiotics to treat secondary infection, steroids, ophthalmic care and intensive care support.

Kawasaki disease 30% of cases have ongoing behavioural disorders, with temper tantrums, poor sleep patterns and internalising abnormalities. Dermatomyositis Upon investigation, characteristically one would find an elevated ESR and CPK along with typical EMG findings of spontaneous muscle fibrillation and short polyphasic muscle potentials. Treatment involves physiotherapy and steroids, immuno-suppressants being reserved for the more resistant cases. psoriasis Non dermatological manifestations of psoriasis include nail pitting, corneal nodules, oedema, liver damage and arthropathy. Psoriatic arthritis has features similar to arthritis associated with UC and Crohn’s disease (NOT coeliac) but the two conditions are probably different.

Causes of vesico-bullous eruptions in the newborn; In XP the skin is usually normal at birth and the first lesions appear on exposed areas between the age of 6 and 24 months. The ectodermal dysplasias are a heterogeneous group of inherited conditions with a primary defect in the teeth, nails, hair or sweat gland function in addition to another abnormality in a ectodermal tissue such as eyes, ears, mucosa, melanocytes and central nervous system. Epidermolysis bullosa Epidermolysis bullosa

This patient has moderate acne and is therefore suitable for second-line therapy. First-line therapy for acne involves the use of topical antibiotics such as tetracyclines, keratolytics or topical retinoids. Second-line therapy involves a 3–4 months’ course of low-dose antibiotics such as tetracyclines or erythromycin, Dianette® (if there is no contraindication), or UVB phototherapy (although this is rarely used now). Third-line therapy involves the use of oral retinoids, although these are prescribed only by specialists in dermatology and carry high risk of teratogenicity.

pityriasis rosea, a self-limiting rash seen in adolescents and young adults that occurs most commonly in spring and autumn. It is thought that it may occur as a postviral rash. The rash consists of circular or oval pink macules with a collarette of scale. It is more prominent on the trunk but also occurs on the limbs. It is usually asymptomatic or causes mild itching, and resolves over 4-8 weeks. No specific treatment is usually indicated for the condition. The first

clinical lesion to appear in pityriasis rosea is the so-called ‘herald patch’, an isolated erythematous patch, appearing on the trunk, surrounded by a ring of scaling skin. A number of oval macules appear on the upper arms, remainder of the trunk and upper thighs some 2–4 days later. Involvement of the hands, feet or scalp is rare. Severe itching is uncommon. A feature of the Sturge-Weber syndrome is the presence of a port-wine stain (capillary angioma) - a benign proliferation of vascular and connective tissue that may be associated with a developmental defect of mature dermal capillaries. Histologically, networks of ectatic vessels in the outer dermis are evident. The lesion is present at birth, is generally unilateral affecting the face, trunk or limbs and is variable in size. Usually, there is a sharp midline borer on the more common unilateral lesions. If areas supplied by the maxillary and ophthalmic divisions of the trigeminal nerve are involved there may be associated angiomas of the underlying meninges, producing neurological manifestations comprising the Sturge-Weber syndrome. It arises sporadically. Jacksonian epilepsy, hemisensory disturbance, hemiplegia, contralateral hemianopia and mental retardation have all been described. Choroidal angioma, glaucoma, buphthalmos (large eye) are ocular manifestations. Skull radiography may demonstrate intracranial ‘tramline’ calcification. Histologically, a strawberry naevus is caused by a benign proliferation of endothelial cells, followed by involution and development of fibrous tissue in the vascular spaces. It occurs in 1% of children and although it sometimes presents at birth, it usually appears shortly afterwards. Clinically, it presents as one or more rapidly growing, dome-shaped, bright-red lumps, most commonly on the head or neck. The lesions grow for the first 12-15 months of life then gradually and spontaneously resolve, in most cases disappearing by the age of seven years. The surface of a lesion may become eroded, crusted or bleed: infection can occur. Large facial lesions may be associated with coarctation of the aorta, and posterior fossa abnormalities can sometimes occur. Laser therapy may be useful for haemangiomas. Tuberose sclerosis is an autosomal-dominant disorder characterised by hamartomas located throughout the body, often prominently involving the central nervous system and skin. Two loci on chromosomes 9 and 16 have been identified. The condition has a variable expression and penetrance and is further characterised by angiofibromas, seizures and mental retardation. Skin features comprise periungual fibromas, cutaneous angiofibromas (adenoma sebaceum) producing small and discrete pink papules mainly affecting the centre of the face, Shagreen patches (collagen naevi) - ie flesh-coloured leathery thickenings of the skin - and ashleafshaped areas of depigmentation that become more visible under Wood’s light. The only treatment is symptomatic, ie anticonvulsants. Neurofibromatosis is another example of a neurocutaneous syndrome (phacodermatoses). This is an autosomal-dominant disorder characterised by neurofibromas affecting the nervous system and skin. The gene responsible is located on chromosome 17 and encodes neurofibromin, which down-regulates the function of the p21 ras oncoprotein. Lesions include acoustic neuroma, schwannoma, café-au-lait spots (hyperpigmented macules), axillary freckling and cutaneous neurofibromas. Systemic manifestations include kyphoscoliosis, bone cysts, phaeochromocytoma, acromegaly and mental deficiency and epilepsy. Type 2 neurofibromatosis is a different entity: there is a propensity in this disease for the development of VIIIth nerve schwannomas or meningiomas. Chronic plaque psoriasis is characterised by pinkish-red hyperkeratotic plaques, which occur especially on extensor surfaces such as knees and elbows. The lower back, ears and scalp are also commonly involved. New plaques of psoriasis occur particularly at sites of skin trauma – the Koebner phenomenon. Skin biopsy of psoriatic plaques reveals acanthosis and parakeratosis, reflecting increased skin turnover. Capillary dilatation within the dermis also occurs, surrounded by a mixed neutrophilic and lymphohistiocytic perivascular infiltrate. Lichen planus is an intensely pruritic eruption of unknown aetiology. It has a very characteristic clinical appearance, composed of grouped, small and shiny, flat-topped violaceous papules with an overlying network of fine white lines (Wickham’s striae). The usual

distribution involves the flexor aspects of the knees, elbows, ankles and wrists, with the mouth being more commonly affected. Lichen planus exhibits Koebner's phenomenon, in which lesions tend to occur at the sites of trauma. This is also the case for vitiligo, psoriasis and plane warts. The disease tends to remit spontaneously between six months and two years. Although topical steroids and antihistamines are helpful for symptomatic relief, often no treatment is required in mild cases. Fading skin papules leave postinflammatory hyperpigmentation, while scalp involvement may produce a scarring alopecia. Nodular prurigo may develop following insect bites, characterised by persistent itching, lichenified papules and nodules over the trunk and limbs. Discoid eczema is a constitutional pattern of eczema; here, the lesions are often vesicular and exudative and may become secondarily infected. The lesions are well-demarcated coin-shaped areas, with one or two patches pre-dating a general eruption by weeks or months. Pruritus may be intense. It typically occurs in middle-aged men (executives), and can be caused by stress, over-washing and a low-humidity environment (air conditioning, central heating). Pyogenic granuloma is an abnormal proliferation of capillaries following trauma or infection. The lesion is often a fleshly, pedunculated vascular nodule that bleeds easily when traumatised.

Henoch-Schönlein purpura presents with purpura in dependent areas (eg buttocks and lower legs). Although it mostly occurs in children between 4 and 15 years of age, it may be seen in slightly older individuals. A 2:1 male to female ratio exists. Postulated aetiology is an exaggerated antigen-antibody reaction with IgA deposition. Antigen triggers may include drugs, foods, immunisation and an upper respiratory tract infection. There may be no specific abnormalities on blood testing, although IgA is elevated in 50% of cases, with a leucocytosis or eosinophilia. Joint pain and renal involvement (leading to microscopic haematuria) are common, as are minor GI bleeds. Prednisolone is given for severe GI or renal involvement, although properly conducted efficacy studies of steroids are hard to come by. Usually recovery occurs within 4 weeks, but severe renal disease may occur in 5% of patients.

Incontinentia pigmenti is a multisystem disorder that shows dominant inheritance. It affects only girls and women clinically as the condition is lethal in males in utero. If a diagnosis is difficult, a look at the mother is always suggested. Clinically there are three phases: (1) the bullous phase – crops of vesicles appear in the first 2 weeks of life; (2) the popular phase – warty papules that flatten out over the skin; and (3) the hyperpigmented phase – pigmentary changes in the form of whorls and streaks that are hypo- and hyperpigmented in nature. There is a different level of melanosis present in each whorl. As this is a multisystem disorder, other clinical symptoms and signs include dental and ocular anomalies, seizures in 30% of cases, rarely learning difficulties, although some children will have a decreased IQ, musculoskeletal abnormalities, alopecia and wiry hair. On skin biopsy, there will be a marble-like lesion that runs in a linear streak, and the skin may appear blistered with a normal or decreased number of melanocytes and hyperkeratosis. There are a large number of intradermal eosinophils but no inflammatory cells. As the child grows older, there will be residual hyperpigmented whorls. The lesions appear in early childhood and then leave a grey streaky pigmentation in adulthood.

There are three main types of tinea infection, which are very difficult to distinguish clinically but have different aetiological factors. 1. Tinea versicolor. The fungus responsible for this infection is Pityrosporum orbiculare (Malassezia furfur). On dark skin, multiple hypopigmented macules with a scaly component are visible. On fair skin, hyperpigmented lesions can be seen. This is not vitiligo, which has a convex edge to it and when investigated has an associated autoimmune component. 2. Tinea capitis. This skin disease is caused by Trichophyton. 3. Tinea corporis. This is commonly known as ringworm and is caused by a dermatophyte infection Microsporum canis. The lesions appear to be annular and erythematous with a scaly, pruritic border and a clear centre. The diagnosis is made by skin scrapings. Treatment is antifungal medication for the skin, hair and nails. It is not known what proportion of children with atopic eczema will benefit from antigen avoidance regimens. The most common foods considered to be involved atopic eczema are cow's milk, egg, wheat, fish, legumes , tomato, nuts, berries and currants, citrus fruit and food additives. House dust mites and pets are of major importance as triggers in atopic eczema. Some patients with atopic eczema are worse during the pollen season or after grass has been cut. Involvement of the whole cutaneous surface may occur but the predominant areas are the face in infants, extensor aspects of the limbs as the child begins to crawl, and the limb flexures in older children. Patients with atopic eczema may develop secondary bacterial infection which presents either as impetigo or folliculitis, or simply as worsening eczema. Mollusca contagiosa are common and atopic patients are at risk of developing severe widespread herpes simplex infections. Egg allergy is a minor cause Dermatits herpetiformis is associated with coeliac disease, presenting as an itchy, blistering rash over elbows, knees, shoulders and buttocks. The skin manifestations of neurofibromatosis include café-au-lait spots and neurofibromata. Café-au-lait spots are also seen in tuberose sclerosis, along with ash-leaf macules and Shagreen patches, which typically occur at the base of the spine and feeling like ‘shark skin’. Erythema Multiforme is associated with mycoplasma infection and also with the use of sulphonamides. Molluscum Contagiosum is caused by a poxvirus. Lesions are flesh coloured papules of 2-4mm in diameter with a central umbilicated area. The condition often resolves spontaneously but may perisist for up to many months. Cryotherapy is a treatment option, however pricking the centre of the lesion with liquid phenol is more commonly considered. Pityriasis rosea is thought to be viral in origin. Typically it starts with a herald patch- a circular lesion often seen on the trunk or abdomen, and then develops into a widespread rash involving principally the trunk, sometimes in a ‘Christmas tree’ distribution as it follows the lines of the ribs. It often has resolved within a month and does not require treatment with antibiotics. Erythema nodosum presents as a painful nodular rash, developing over a few days and typically affecting the shins. It occasionally results in residual pigmented areas of the skin. Causes include infections- Streptococcal, TB and leptospiriosis, drugs- penicillins, sulphonamides, oral contraceptives and tetracyclines, inflammatory bowel disease and connective tissue disease.

Erythema multiforme is a common skin condition, which results in a generalised, erythematous maculopapular rash with characteristic ‘target’ lesions, occurring primarily on the hands, feet and extensor aspects of the limbs. It often resolves within 10 days. The extreme form of erythema multiforme is Stevens Johnson syndrome, which involves mucosal membranes and results in bullae formation. This condition requires treatment with corticosteroids. Eczema Herpeticum is due to herpes simplex infection and requires treatment with systemic antibiotics and antiviral medication. Both Pityriasis rosea and molluscum contagiosum often resolve spontaneously, without treatment. The mite Sarcoptes Scabei, which is commonly spread by close direct physical contact, causes scabies. The mite burrows into the skin, laying its eggs in the stratum corneum layer. It occurs more commonly in immuno-compromised children and those with Down’s syndrome. It is important to treat the whole family when treating the index case. Waardenburg’s syndrome is dominantly inherited and characterised by a white forelock, sensorineural hearing loss and heterochromic irises. There is occasionally hypopigmentation. Kawasaki disease, Atopic eczema and Cockayne’s syndrome are not characterised by hypopigmentation. Cockayne’s syndrome is associated with short trunk and long limbs, developmental delay, optic atrophy and dysfunction of the cerebellum. Napkin Candida infection involves the flexures and has characteristic satellite lesions. It follows the pattern of spreading outwards from the anus. Inspection of the mouth for oral candidiasis is essential and topical nystatin is the treatment of choice for the nappy area. Morphoea presents as a very firm, white or violaceous patch of skin on any body site, but more commonly on the thighs, trunk and upper arms. The disease occurs most commonly in children or young adults. Developing morphoea lesions have a well-demarcated red or violet peripheral edge. As disease activity burns out, the edge assumes the same colour as the central lesion, and the lesion itself becomes very firm with an atrophic glazed surface appearance. A linear variant of morphoea may be seen on the scalp and face of young children, and is known as ‘en coup de sabre’. Some commentators postulate that the disease may be linked to infection with Borrelia burgdorferi, although circulating antibodies or spirochaetes are not identified in every patient. In support of this hypothesis, there are anecdotal case reports that some patients with early morphoea lesions appear to respond to tetracycline antibiotics. Isotretinoin is indicated for the treatment of severe inflammatory acne. However, it causes marked dryness of the skin and mucous membranes, especially the lips, and can result in minor nosebleeds. Due to its teratogenicity, pregnancy must be excluded prior to its initiation and during treatment as well as for 1 month after treatment. Other side-effects are paronychia, meatitis in males and contact lens problems due to dryness of the eyes. Abnormalities of serum lipids and liver function tests should be excluded before treatment and sought after 4, and perhaps 8, weeks of treatment. Tinea incognito is the name given to tinea when the clinical appearance has been altered by inappropriate treatment, usually a topical steroid cream. Tinea is an infection with a dermatophyte fungus. The result is that the original infection slowly extends. Often the patient and/or their doctor believe they have a dermatitis, hence the use of a topical steroid cream. The steroid cream dampens down inflammation so the condition feels less irritable. But when the cream is stopped for a few days the itch gets worse, so the steroid cream is promptly used again. The more steroid applied, the more extensive the fungal infection becomes.

Treatment of eczema can be problematic. It is worthwhile giving parents advice about simple, everyday measures that can improve the eczema: using non-biological washing powder; wearing cotton clothes as opposed to artificial fibres; and not using soaps or shampoos. Use of a bath oil (eg Oilatum) is beneficial and aqueous cream can be used as ‘soap’ to good effect. Regular emollient use is important; however, parents can find using very greasy

products hard work because it involves a lot of washing of clothes. The aim is to keep the skin from feeling dry at any time of day. Sedating with older types of antihistamines at night does not help to reduce itching but used occasionally in large doses provides a sedative effect which may improve sleep. Once all these measures are in use, but the eczema is still not controlled, escalation of treatment would be appropriate. There is no evidence for the benefit of topical antibiotics. All are minor criteria. Major criteria include:           

facial angiofibroma periungal/ungal fibroma shagreen patches hypomelanotic macules (more than three) cortical tuber subendymal nodule subendymal giant-cell astrocytoma multiple retinal hamartomas cardiac rhadomyosarcoma renal angiolipoma lymphangiomyomatosis.

Minor criteria are dental enamel pits, radial migration lines in the cerebral white matter and retinal achromic patches. Two major features and one minor feature are required for a definite diagnosis of tuberous sclerosis. Tuberous sclerosis is an autosomal dominant condition; the genetic loci involved are on chromosome 9q34 (TSC1) and chromosome 16p13 (TSC2).