The diagnosis of scabies can often be made clinically in patients with a pruritic rash and characteristic linear burrows. Definitive testing relies on the identification of mites or their eggs, eggshell fragments, or scybala. This is best undertaken by placing a drop of mineral oil directly over the burrow on the skin and then superficially scraping longitudinally and laterally across the skin with a scalpel blade. (Avoid causing bleeding.) Scraping 15 or more burrows often produces only 1 or 2 eggs or mites, except in a case of crusted scabies, in which many mites will be present. The sample is placed on a microscope slide and examined under low and high power. Potassium hydroxide should not be used, since it can dissolve mite pellets. Failure to find mites is common and does not rule out the diagnosis of scabies.

Atopic dermatitis (AD), also called atopic eczema, is a common chronic or recurrent inflammatory skin disease and affects 15-20% of children and 1-3% of adults worldwide. It is characterized by acute flare-ups of eczematous pruritic lesions over dry skin.The incidence has increased by 2- to 3-fold during the past decades in industrialized countries.Some of the most valuable AD prevalence and trend data have come from the International Study of Asthma and Allergies in Childhood (ISAAC). This is the biggest (close to 2 million children in 100 countries) and only allergy study that has taken a truly global approach. The strength of the study is the use of a uniformly validated methodology allowing a direct comparison of results between paediatric populations all over the world (http://isaac.auckland.ac.nz/index.html).

Histology of psoriasis is characterised by parakeratosis (cell nuclei within stratum corneum) and thickened projections of the prickle cell layer of keratinocytes (psoriasiform hyperplasia or acanthosis). Orthokeratosis refers to the formation of a pathological anuclear keratin layer in the skin.The stratum granulosum is actually thinned or absent in patients with psoriasis.

The clinical presentation of lichen planus has several variations, as follows:- Hypertrophic lichen planus- Atrophic lichen planus- Erosive/ulcerative lichen planus- Follicular lichen planus (lichen planopilaris)- Annular lichen planus- Linear lichen planus- Vesicular and bullous lichen planus- Actinic lichen planus- Lichen planus pigmentosus- Lichen planus pemphigoides

Clinical diagnosis of neurofibromatosis type 1 requires the presence of at least 2 of 7 criteria. Many of these signs do not appear until later childhood or adolescence, and thus confirming the diagnosis often is delayed despite a suspicion of NF1. The 7 clinical criteria used to diagnose NF1 are as follows:- Six or more café-au-lait spots or hyperpigmented macules greater than 5 mm in diameter in prepubertal children and greater than 15 mm in postpubertal- Axillary or inguinal freckles (>2) – Two or more typical neurofibromas or one plexiform neurofibroma- Optic nerve glioma- Two or more iris hamartomas (Lisch nodules), often identified only through slit-lamp examination by an ophthalmologist- Sphenoid dysplasia or typical long-bone abnormalities such as pseudarthrosis- A first-degree relative (e.g., mother, father, sister, brother) with NF1

Hirsutism is the growth of excess hair in androgen dependent areas or in a male pattern. The phenomenon is found in conditions where there is abnormal androgen action. This can occur in adrenal lesions including congenital adrenal hyperplasia, and Cushing syndrome, or a failure to produce adequate female hormones such as PCOS and premature menopause. Similarly, drugs such as anabolic steroids, danazol and minoxidil can also cause hirsutism. Delayed puberty is unlikely to cause hirsutism.

Topical benzoyl peroxide is used for the treatment of mild to moderate acne vulgaris. It is actually a peeling agent and it clears the pores and reduces the bacterial cell count.

The most probable lesion in the patient is a dermoid cyst.Rationale:Dermoid cysts are embryological remnants and may be lined by hair and squamous epithelium (like teratomas). They are often located in the midline and may be linked to deeper structures resulting in a dumbbell shape to the lesion. Complete excision is required as they have a propensity to local recurrence if not excised.Note:Desmoid tumours are a different entity entirely. These lesions most commonly develop in ligaments and tendons. They are also referred to as aggressive fibromatosis and consist of dense fibroblastic lesions (resembling scar tissue). They should be managed in a similar manner to soft tissue sarcomas.

Leiner disease belongs to a heterogeneous group of disorders associated with permanent or temporary complement C5 plasma deficiency. It is a rare disease that follows an autosomal recessive pattern of transmission. It is prevalent in female, breast-fed babies. The hallmark of this syndrome is severe diarrhoea, severe generalized seborrheic dermatitis, central nervous system defects, marked wasting, recurrent local and systemic infections, and failure to thrive.

The sign being elicited in this patient is Nikolsky’s sign. Based on the findings, the patient is suffering from toxic epidermal necrolysis.Nikolskys sign: Rubbing the skin causes exfoliation of the outer layer and usually blistering within a few minutes. Other options:- Cullen’s sign: Periumbilical bruising due to intra-abdominal haemorrhage. If the discolouration is seen in the flanks, it is called Cullen’s sign. Underlying pathology includes ruptured ectopic pregnancy and haemorrhagic pancreatitis. – Forscheimer’s sign: It is a fleeting exanthem that is seen as small, red spots (petechiae) on the soft palate. Associated with rubella and glandular fever. Gorlin’s sign: It is the ability to touch the tip of the nose with the tongue. Increased incidence in children with connective tissue disorders, e.g. Ehler Danlos syndrome. – Auspitzs sign: These are small bleeding points left behind when psoriatic scales are lifted off. It is not a very sensitive or specific sign. Other cutaneous signs include:- Hair collar sign: It is a collar of hypertrichosis around an area of cranial dysraphism.- Hertoghe’s sign (Queen Anne’s sign): It is the loss of lateral one-third of eye-brows. It is associated with numerous conditions, including lupus, HIV, and hypothyroidism. – Dariers sign: It is the swelling, itching and erythema that occurs after stroking skin lesions of a patient with systemic mastocytosis or urticarial pigmentosa. – Dermatographism: Rubbing the skin causes a raised, urticarial lesion. – Koebners phenomenon: It is the appearance of new skin lesions in areas of trauma.- Breakfast, lunch, and dinner sign: Linear pathway of a group of three to five papules caused by the common bed bug, Cimex lectularius. – Buttonhole sign: In type 1 neurofibromatosis, neurofibromas can be invaginated with the finger back into the subcutis. The nodule will reappear after the release of pressure. The sign is also positive for dermatofibromas. – Crowe’s sign: Axillary freckling seen in type I neurofibromatosis.

Alopecia areata is seen in 6-8.8% of patients with Down syndrome, but only 0.1% of patients with alopecia areata have Down syndrome. The high frequency of alopecia areata in patients with Down syndrome suggests that a genetic linkage for alopecia areata may exist on chromosome 21.

Various types of birthmarks are commonly seen in children of different age groups. Birthmarks can be broadly classified as pigmented and vascular birthmarks. Port-wine stain (nevus flammeus) is an example of a vascular birthmark, and is characterized by a reddish-purple discoloration of the skin due to abnormal underlying skin vasculature. Port-wine stain has also been associated with vascular diseases like Sturge-weber syndrome, which is a congenital neurocutaneous disorder. In Sturge-weber syndrome, the port-wine stain affects the skin around the ophthalmic branch of trigeminal nerve.

Psoriasis is a chronic inflammatory skin disease that is mainly due to the interplay between keratinocytes, dermal vascular cells, and antigen-presenting cells. There are five main types of psoriasis based on the type and severity of the lesions it produces. A useful tool to determine the extent and severity of psoriasis is the Psoriasis Area and Severity Index (PASI) score, which takes into account the percentage of a specific area affected by psoriasis in combination with severity, which in turn is assessed by the presence of desquamation, induration, and erythema.

Incontinentia pigmenti is a genetic condition that affects females more than males. It usually manifests in the skin but can affect other parts of the body as well. It presents with a blistering rash that may evolve into wart-like growths. Hyperpigmentation and hair loss are also present, as well as eye and teeth abnormalities. Clinically there are three phases: 1- the bullous phase – crops of vesicles appear in the first 2 weeks of life|2- the papular 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.

Henoch-Schönlein purpura (HSP) rashes are commonly found on the legs, feet, and buttocks while Immune thrombocytopenia (ITP) rashes manifest predominantly on the lower legs. HSP happens following a sore throat while ITP usually happens following an URTI or Flu. HSP is an inflammation of a blood vessel (vasculitis) while ITP is immune mediated insufficiency of platelets.

The baby most probably has dystrophic epidermolysis bullosa, a primarily autosomal dominant disorder associated with keratin 5 and 14 defects. Initial management consists of supportive measures such as protecting the skin.

Favus is a fungal infection of the scalp, resulting in the formation of a yellowish crusted plaque over the scalp and leads to scar formation with alopecia. Tinea capitus is a fungal infection of the scalp resulting in scaling and non scarring hair loss. Folliculitis presents with multiple perifollicular papules which can be caused by both bacteria and fungi. Cradle cap usually affects infants where the whole scalp is involved. It can lead to hair loss and responds to topical antifungals and keratolytics.

Kaposi varicelliform eruption (KVE) is the name given to a distinct cutaneous eruption caused by herpes simplex virus (HSV) type 1, HSV-2, coxsackievirus A16, or vaccinia virus that infects a pre-existing dermatosis. Most commonly, it is caused by a disseminated HSV infection in patients with atopic dermatitis (AD) and, for this reason, is often referred to as eczema herpeticum (EH).Kaposi varicelliform eruption (KVE) is now known to occur in children of any age and in adults, however, most patients (56%) are aged 15-24 years.

Morphea, also known as localized scleroderma, is a disorder characterized by excessive collagen deposition leading to thickening of the dermis, subcutaneous tissues, or both. Morphea is classified into circumscribed, generalized, linear, and pansclerotic subtypes according to the clinical presentation and depth of tissue involvement. Unlike systemic sclerosis, morphea lacks features such as sclerodactyly, Raynaud phenomenon, nailfold capillary changes, telangiectasias, and progressive internal organ involvement. Morphea can present with extracutaneous manifestations, including fever, lymphadenopathy, arthralgias, fatigue, central nervous system involvement, as well as laboratory abnormalities, including eosinophilia, polyclonal hypergammaglobulinemia, and positive antinuclear antibodies.

When topical agents are insufficient or not tolerated, or in cases of moderate to severe acne, especially when the chest, back and shoulders are involved, systemic antibiotics are often considered the next line of treatmentSystemic antibiotics should not be used to treat mild acne because of the risk of increasing resistance. The additional use of nonantibiotic topical agents in combination with oral antibiotics should be considered. Topical retinoids with oral antibiotics may give a faster response and be more effective than either drug used alone.Treatment with tetracyclines and erythromycin reduces P. acnes within the follicles, thereby inhibiting the production of bacterial-induced inflammatory cytokines. These agents also have inherent anti-inflammatory effects, such as suppressing leukocyte chemotaxis and bacterial lipase activity.

The most appropriate next step in the management of this patient would be to use E45 cream instead of soap. Using a greasier emollient and an antihistamine at night can also be trialled..Management of eczema:Treatment of eczema can be problematic, and thus, parents should be advised regarding simple, everyday measures that can relieve the symptoms. These include:- Using non-biological washing powder- Wearing cotton clothes as opposed to artificial fibres- Avoiding the use of soaps or shampoos and using E45 Cream as an alternative.- Additional use of bath oil (e.g. Oilatum) is found to be beneficial.- Regular emollient use is recommended and essential. 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 when used in large doses, they occasionally provide a sedative effect which may improve sleep. If all these measures are in use, but the eczema is still not controlled, the escalation of treatment would be appropriate. Note: There is no evidence for the benefit of topical antibiotics.

Erythema nodosum (EN) is an acute, nodular, erythematous eruption that usually is limited to the extensor aspects of the lower legs. Chronic or recurrent erythema nodosum is rare but may occur.Currently, the most common cause of erythema nodosum is streptococcal infection in children and streptococcal infection and sarcoidosis in adults.The eruptive phase of erythema nodosum begins with flulike symptoms of fever and generalized aching. Arthralgia may occur and precedes the eruption or appears during the eruptive phase. Most lesions in infection-induced erythema nodosum heal within 7 weeks, but active disease may last up to 18 weeks. In contrast, 30% of idiopathic erythema nodosum cases may last more than 6 months. Febrile illness with dermatologic findings includes abrupt onset of illness with initial fever, followed by a painful rash within 1-2 days.

The most probable cause for the patient’s presenting symptoms is Sarcoptes scabeii.Scabies:The boy in the scenario presents with a pruritic rash affecting the palms of the hands, especially in the web spaces between the fingers. Additionally, the fact that his sister is showing similar symptoms is an indication of its infectivity. The female Sarcoptes scabiei var hominis mite burrows into the webs of fingers and the sides of digits as seen in the child.This parasitic skin infestation presents typically with nocturnal itching. Other options:- Herpes simplex virus type 1 (HSV-1): This can affect this age group but would usually present with a vesicular perioral rash with associated erythema. – Human papillomavirus (HPV): Cutaneous human papillomavirus infection causes warts, which can form a dome and fleshy shaped lesions on the palms of the hands, but these are not usually itchy. Similar to the causative agent in the boy, they are contagious.- Poxvirus: These viruses cause molluscum contagiosum which presents as dome-shaped lesions anywhere on the body, rather than specifically in palms of hands or finger webs as seen in the boy. Poxviruses are also very infectious.- Staphylococcal infection: This causes impetigo, which presents with yellow discharge and underlying erythema. Impetigo is not usually itchy and can present on any part of the body, rather than the specific areas seen in the boy.

Scabies is a dermatological condition caused by infestation of the Sarcoptes Scaibie. The tiny mite, often unseen by the naked human eye, is able to burrow into the stratum corneum where it lays its eggs, causing irritation and a rash related to the immune response against the mite and its eggs, saliva and faeces. On examination, the pathognomic small burrows are often seen on the skin along with small red papules and scratch marks| granulomatous nodules may also be seen especially in darker skin types. Other clinical subtypes such as bullous, and Norwegian (crusted) also exist. Common areas of infection include the hands, wrists, and the interdigital spaces. Infestation can also occur on the genital area, the buttocks, feet, ankles, flexor surfaces. First line treatment is with permethrin 5% dermal cream. It is important that all members of the household are also treated at the same time, and that contaminated bedding, clothes and furniture is adequately disinfected. Scabies is usually associated with overcrowded conditions.

The most common organism responsible for tinea capitis is Trichophyton tonsurans.Tinea is a term given to dermatophyte fungal infections. There are three types of tinea, depending on what part of the body is infected:- Tinea capitis – scalp- Tinea corporis – trunk, legs or arms- Tinea pedis – feetTinea capitis (scalp ringworm):It is a cause for scarring alopecia mainly seen in children.If untreated, it can form a raised pustular, spongy/boggy mass called a kerion.The most common cause of tinea capitis in the UK and the USA is Trichophyton tonsurans.Tinea can also be caused by Microsporum canis acquired from cats or dogs.The diagnosis of tinea capitis and identification of the organism is possible from the skin lesions:- Scalp scrapings and Potassium hydroxide (KOH) mounts.- Wood’s lamp: Microsporum canis produces a green fluorescence under Wood’s lamp examination.Treatment: – Oral antifungals: terbinafine for Trichophyton tonsurans infections.- Griseofulvin for Microsporum infections. – Topical ketoconazole shampoo is recommended for the first two weeks to limit the transmission of the infection.

Port-wine stains are a type of vascular birthmark caused by the abnormal development of capillaries in the skin. These pinkish-purplish discolorations present at birth and are associated with medical conditions such as Sturge-Weber syndrome, a neurocutaneous disorder involving the leptomeninges. Port wine stains are therefore associated with epilepsy, glaucoma or intellectual disability common in Sturge-Weber syndrome. Additional complications of Port wine stains include a loss of function if near the eye or mouth due to hypertrophy, or glaucoma if near the eyelid.

Scabies infection in neonates typically manifests as nodular eruptions involving the face, neck, scalp, palms, and soles in contrast to the predominant involvement of the hands, wrists, elbows, and ankles in adults. Differential diagnoses for the nodular eruption in neonates are broad, and scabies often is misdiagnosed as Langerhans cell histiocytosis, urticaria pigmentosa, or another pruritic, bullous, or lymphoproliferative dermatosis. Histopathology of the reactive nodules usually is not diagnostic, because scabetic organisms are often unidentified and histologic findings are nonspecific. Furthermore, because of the atypical presentation, scabies in children is often missed until persons in close contact with the child present with similar symptoms. Thus, a thorough history and close follow-up are crucial to avoid misdiagnosis and unnecessary aggressive treatment. Moreover, synchronized treatment of patients and their close contacts is needed to ensure the success of therapy, considering that relapse is 2-3 times more frequent in children and infants

Miliaria is a common skin disease caused by blockage and/or inflammation of eccrine sweat ducts. Miliaria is frequently seen in hot, humid or tropical climates, in patients in the hospital, and in the neonatal period. Miliaria is also known as sweat rash.Based on the level of the sweat duct obstruction, miliaria is divided into three subtypes:- Miliaria crystallina (sudamina), caused by obstruction of the sweat ducts close to the surface of the skin (epidermis)|- Miliaria rubra, caused by obstruction of the sweat ducts deeper in the epidermis|- Miliaria profunda (tropical anhidrosis), the result of sweat leaking into the middle layer of skin (dermis).Miliaria crystallina appears as 1–2 mm superficial clear blisters that easily break. The blisters can look like beads of sweat. There is no inflammation. The blisters are usually seen widely spread on the head, neck, and upper trunk.Miliaria rubra is the most common type of miliaria results in red, 2–4 mm, non-follicular papules and papulovesicles. They are very itchy. Background erythema is often present. In children, miliaria affects the skin folds of the neck, axilla or groin. In adults, miliaria often affects the upper trunk, scalp, neck and flexures, particularly areas of friction with clothing. Miliaria pustulosa is a variant of milia rubra in which there are pustules.Miliaria profunda describes asymptomatic deep papules. The flesh–coloured, 1–3 mm diameter papules usually arise on the trunk and extremities.Mild Topical steroids can be used as a treatment

Erythema infectiosum is an acute viral illness caused by Parvovirus B19. It is usually a mild flu-like illness and produces a maculopapular rash, appearing initially on the cheeks and then spreading towards extremities. The rash usually spares the palms and soles and gives a slapped appearance to the cheeks. It can be described as having a fishnet appearance on the body.

Atopic dermatitis is an allergic condition which is more apparent in those children who have a positive family history in their 1st or 2nd degree relatives. In some cases, there might be a positive history of bronchial asthma. The best treatment option in this case would be topical application of 1% hydrocortisone ointment to the affected areas of the child. We cannot prescribe a strong ointment to the face because it may lead to skin atrophy, telangiectasia and other steroid related topical complications.

Among the given options, psoriasis is not associated with hypertrichosis.The causes of hypertrichosis include:- Drugs: minoxidil, ciclosporin, and diazoxide.- Congenital hypertrichosis lanuginosa and congenital hypertrichosis terminalis.- Porphyria cutanea tarda- Anorexia nervosa

Café-au-lait spots is hyperpigmented lesions that vary in colour from light brown to dark brown, with borders that may be smooth or irregular. Causes include:
Neurofibromatosis type I
McCune–Albright syndrome
Legius syndrome
Tuberous sclerosis
Fanconi anaemia
Idiopathic
Ataxia-telangiectasia
Basal cell nevus syndrome
Benign congenital skin lesion
Bloom syndrome
Chediak-Higashi syndrome
Congenital nevus
Gaucher disease
Hunter syndrome
Maffucci syndrome
Multiple mucosal neuroma syndrome
Noonan syndrome
Pulmonary Stenosis
Silver–Russell syndrome
Watson syndrome
Wiskott–Aldrich syndrome

Erythema nodosum is the most common type of inflammation of the subcutaneous fat tissue, referred to as panniculitis. Erythema nodosum appears as painful, erythematous round lumps, usually symmetrically on the anterior aspect of lower extremities. These lesions are self-limiting and tend to resolve within 2-8 weeks without undergoing necrosis. There are various causes of erythema nodosum, but the most important among children is the streptococcal throat infection. Other causes include autoimmune conditions like sarcoidosis, inflammatory bowel disease, mycobacterial infection (TB), and drugs like penicillin and sulphonamides. Coeliac disease is not linked with the formation of erythema nodosum.

Erythema multiforme is a skin rash characterized by the eruption of macules, papules, and target-like lesions. The target or iris lesions appear rounded with a red centre surrounded by a pale ring, which in turn is surrounded by a dark red outer ring. These are acute and self-limiting, mostly appearing on the distal extremities along with palmoplantar involvement. The disease affects the mucous membrane and orbits as well. The most common infectious cause is herpes simplex virus 1 and 2 to a lesser extent. Inflammation of the adipocytes underlying the skin is referred to as erythema nodosum, and it is not a feature of EM.

The most common cause of acute urticaria is a viral infection. Individual lesions typically are short-lived and last less than 24 hours. Urticaria can be due to or can be made worse by cold temperatures. One of the other causes of urticaria is salicylic acid.

Koebner’s phenomenon describes skin lesions that occur on damaged skin, usually in a linear fashion at the site of injury. Conditions which exhibit true Koebnerisation include psoriasis, lichen planus, lichen sclerosis, vitiligo, Kaposi sarcoma and SLE. Conditions such as erythema nodosum or multiforme, or Lyme disease and Impetigo do not exhibit Koebner’s phenomenon.

Pityriasis rosea is a common, acute exanthem of uncertain aetiology. Viral and bacterial causes have been sought, but convincing answers have not yet been found. Pityriasis rosea typically affects children and young adults. It is characterized by an initial herald patch, followed by the development of a diffuse papulosquamous rash. The herald patch often is misdiagnosed as eczema. Pityriasis rosea is difficult to identify until the appearance of characteristic smaller secondary lesions that follow Langer’s lines (cleavage lines). Several medications can cause a rash similar to pityriasis rosea, and several diseases, including secondary syphilis, are included in the differential diagnosis. Typically, only symptomatic treatment of pruritus with lotions, oral antihistamines, and/or a short course of topical steroids is necessary.

Eczema herpeticum (also called Kaposi varicelliform eruption) is a disseminated viral illness usually associated with lymphadenopathy.It is most often caused by Herpes Simplex type 1 or type 2. Occasionally, other viruses such as coxsackievirus A16 may cause eczema herpeticum. Affected children usually develop itchy blisters and fever after coming in contact with an affected individual who may or may not display cold sores.It is characterised by an itchy and sometimes painful cluster of blisters most commonly on the face initially. This spreads over one to several weeks resulting in further crops of blisters which can become confluent. Lymphadenopathy and fever are common in these patients.The severity varies from mild illness to life-threatening, especially in immunocompromised children or young infants. It is markedly more common in children with atopic dermatitis. It is one of the few dermatological emergencies, and oral antivirals are often indicated. Referral to an ophthalmologist may be needed if there is eyelid or eye involvement. Occasionally, superadded skin infections caused by staphylococci and streptococci can occur.

Capillary haemangiomas (strawberry naevi) are very common benign tumours that may appear in infancy. This particular case requires a close follow-up to monitor the naevus’ size and make sure it doesn’t expand or gets bigger, affecting the baby’s visual field.It is more common in preterm babies and girls are 3x more commonly affected than boys. It presents at birth in 30%, and is a focal and solitary in 80% of cases, most commonly found on the head and neck (60%), followed by the trunk (25%) and extremities (15%).

Topical treatments are useful in the treatment of mild Psoriasis, or as adjuvant therapy in ultraviolet and systematic treatments. These treatments include moisturisers, dithranol, coal tar, salicylic acid, topical immunomodulators such as calcineurin, topical retinoids, Vitamin D analogues and topical steroids. Topical steroids are known to have a number of side effects such as striae, atrophy of the skin, telangiectasia, acneiform rash, and easy bruising. Localised pustular psoriasis is also associated with topical steroids in higher doses. Use of more than 500 g of hydrocortisone or 50 g clobetasol propionate have been shown to suppress adrenal function. Calcitriol, a vitamin D analogue, is only available as an ointment and does not stain clothes and skin the way dithranol and coal tar are known to.