Scarlet fever is a childhood infectious disease caused by group A Streptococcus. It produces a papular rash, which is classically described as a sand-paper rash. The rash initially appears on the trunk, groin, and underarms and then spreads to extremities, usually sparing the palms and soles. Circumoral area is also spared, giving it pallor-like appearance. Diseases like erythema multiforme, contact dermatitis, staphylococcal scalded skin syndrome, and rubella produce a rash that classically affects the palms and soles.

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.

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 disorder, e.g. Ehler Danlos syndrome. – Auspitzs sign: These are small bleeding points are 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.

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 diagnosis for this patient’s symptoms is psoriasis. Psoriasis:Chronic plaque psoriasis is characterised by pinkish-red hyperkeratotic plaques, which occur mainly on extensor surfaces such as knees and elbows. The lower back, ears and scalp can also be involved. Koebner phenomenon: Psoriasis typically exhibits this phenomenon where new plaques of psoriasis occur particularly at sites of skin trauma. Diagnosis: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.

A Mongolian spot can be present in new born babies which usually appears over the back and fades with time. There is nothing to worry about.

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.

Sturge-Weber syndrome (SWS), also called encephalotrigeminal angiomatosis, is a neurocutaneous disorder with angiomas that involve the leptomeninges (leptomeningeal angiomas [LAs]) and the skin of the face, typically in the ophthalmic (V1) and maxillary (V2) distributions of the trigeminal nerve. The hallmark of SWS is a facial cutaneous venous dilation, also referred to as a nevus flammeus or port-wine stain (PWS).Signs and symptoms:SWS is generally diagnosed clinically, based on the typical cutaneous, central nervous system (CNS), and ocular abnormalities associated with it.Neurological signs include the following:Developmental delay/intellectual disabilityLearning problemsAttention deficit-hyperactivity disorderInitial focal seizures progressing to frequent, secondarily generalized seizuresIncreasing seizure frequency and duration despite the use of antiepileptic drugs (AEDs)Increasing duration of a transient postictal deficitIncrease in focal or diffuse atrophy – Determined by serial neuroimagingProgressive increase in calcificationsDevelopment of hemiparesisDeterioration in cognitive functioningPhysical signs of SWS are as follows:Port-wine stainMacrocephalyOcular manifestationsSoft-tissue hypertrophyHemiparesisVisual lossHemianopsiaOcular involvement in SWS may include the following signs:BuphthalmosGlaucomaTomato-catsup colour of the fundus (ipsilateral to the nevus flammeus) with glaucomaConjunctival and episcleral haemangiomasDiffuse choroidal haemangiomasHeterochromia of the iridesTortuous retinal vessels with occasional arteriovenous communications

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.

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

Mongolian spots, otherwise called congenital dermal melanocytosis, are pigmented birthmarks. They are usually located on the buttocks or back and although they’re usually present at birth, they may appear soon after. They are flat and have a blue-grey colour (bruise-like). They are benign and present no health risk.

Pityriasis amiantacea: This condition is characterized by thick, asbestos-like scales on the scalp and is often associated with psoriasis or seborrheic dermatitis.

Infantile seborrhoeic dermatitis: Also known as cradle cap, this condition causes greasy, yellowish scales on the scalp.

Tinea capitis: A fungal infection of the scalp that leads to scaling, hair loss, and sometimes redness and swelling.

Cutaneous lupus erythematosus: While lupus can cause skin lesions, it is less commonly associated with a scaly scalp compared to the other conditions listed. It can cause hair loss and erythema, but significant scaling is not a primary feature.

Scalp psoriasis: This condition is well-known for causing thick, silvery scales on the scalp

Erythema multiforme lesions typically heal without scarring. Other options:- In erythema multiforme, lesions are typically symmetrical and acral, i.e. on the hands, feet and limbs. – HSV is a common cause of erythema multiforme in children, accounting for at least 50% of cases| the lesions typically have damaged skin in the centre and are dusky and bullous (in contrast to urticaria, where the centre of the lesion is normal).

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.

Ichthyosis vulgaris presents clinically with xerosis, hyperkeratosis, excess scaling, keratosis pilaris, and palmar and plantar hyperlinearity. It most commonly affects the extensor surfaces of the limbs and spares flexor surfaces, the face, and the neck.

The skin lesion described is the typical presentation of a keloid scar.Keloid scars extend beyond the limits of the incision.Note:Surgical wounds are either incisional or excisional and either clean, clean-contaminated or dirty. The main stages of wound healing include:- Haemostasis:It occurs minutes to hours following injury. It is characterised by the vasospasm in adjacent vessels, platelet plug formation and generation of fibrin rich clot.- Inflammation: It occurs typically 1-5 days after the injury. Neutrophils migrate into the wound (this is often impaired in diabetes). Growth factors, including basic fibroblast growth factor and vascular endothelial growth factor, are released in this phase. Fibroblasts replicate within the adjacent matrix and migrate into wound, while macrophages and fibroblasts couple matrix regeneration and clot substitution.- Regeneration: It occurs typically between 7-56 days after the injury. The factors that stimulate this phase are platelet-derived growth factor and transforming growth factor. They stimulate fibroblasts and epithelial cells. Fibroblasts produce a collagen network. Furthermore, they cause angiogenesis and thus wound healing.- Remodelling: This is considered the longest phase of the healing process and may last up to one year (or longer). During this phase, fibroblasts become differentiated (myofibroblasts), and these facilitate wound contraction. Collagen fibres are remodelled, and microvessels regress, leaving a pale scar.Clinical correlation:Abnormal scar formation:- Hypertrophic scars:It is the condition where excessive amounts of collagen are produced within a scar. Nodules may be present histologically containing randomly arranged fibrils within and parallel fibres on the surface. The tissue itself is confined to the extent of the wound itself and is usually the result of a full-thickness dermal injury. They may go on to develop contractures.- Keloid scars: This is also a condition where excessive amounts of collagen occur within a scar. A keloid scar will typically pass beyond the boundaries of the original injury. They do not contain nodules and may occur following even trivial injury. They do not regress over time and may recur following removal.

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.

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

Breslow thickness is measured from the top of the granular layer of the epidermis (or, if the surface is ulcerated, from the base of the ulcer) to the deepest invasive cell across the broad base of the tumour (dermal/subcutaneous) as described by Breslow.Margins of excision-Related to Breslow thicknessLesions 0-1mm thick – 1cmLesions 1-2mm thick – 1- 2cm (Depending upon site and pathological features)Lesions 2-4mm thick – 2-3 cm (Depending upon site and pathological features)Lesions >4 mm thick – 3cmMarsden J et al Revised UK guidelines for management of Melanoma. Br J Dermatol 2010 163:238-256.

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.

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.

One of the options of Psoriasis treatment is vitamin D analogues i.e. calcipotriol. Acne is exacerbated by steroids. Erythema nodosum can be caused by various diseases and the treatment of the primary condition resolves the symptoms. Lipomas requires surgery, whereas Steven-Johnson syndrome requires use of steroids and eliminating the culprit drug, which is one of the most common causes.

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 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.

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.

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 patient’s symptoms are most likely due to phenytoin intake.Note:Hypertrichosis occurs in 5–12% of patients on phenytoin and is most prominent on the extremities. Other options:- Hypertrichosis is the excess hair growth, whereas hirsutism is the development of male-pattern-dependent hair growth, as seen in polycystic ovarian syndrome. – A Becker’s naevus is associated with localised hypertrichosis in the naevus. – Cyclosporine intake can typically lead to diffuse hair growth that begins within 2–4 weeks of starting the drug. – Hereditary gingival fibromatosis is associated with variable hypertrichosis occurring on the eyebrows, face, limbs and mid-back.

Sturge-Weber syndrome is a genetic condition affecting various blood vessels. I causes brain, eye, and skin abnormalities, including three major features: port-wine birthmark, leptomeningeal angioma, and glaucoma. Most people are born with a port-wine birthmark that is usually located on the face, including the eyelid.

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.