This patient is most likely suffering from hand, foot mouth disease which is caused by coxsackie virus A16. Its incubation period ranges from 5-7 days and only symptomatic treatment is required.

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 or ulceration. 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), drugs like penicillin and sulphonamides, and malignancies like some leukemias and lymphomas.

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.

Nonspecific triggers of inflammation in patients with atopic dermatitis may include physical or chemical irritants. The following simple measures should be followed in daily life to reduce the frequency and severity of irritant-induced atopic dermatitis flares :Skin care products that contain alcohol and astringents should be avoided.New clothes should be laundered before use to remove formaldehyde and other chemicals.Liquid detergents are preferred over powder detergents for laundering clothes, as liquids are easier to rinse out. A second rinse cycle may also improve removal of residual detergent.Patients should shower immediately after swimming in chlorinated pools and should subsequently apply moisturizer.Fragrance-free skin products that are hypoallergenic or made for sensitive skin may be less irritating than other kinds of skin products.Prenatal and postnatal probiotic supplementation may be helpful in preventing the development of atopic dermatitis in young children. In a 2008 meta-analysis, the most commonly studied probiotic was Lactobacillus rhamnoses GG. Larger, randomized controlled studies are needed to confirm these initial findings.Breastfeeding during the first 4 months of life may reduce the incidence and severity of childhood atopic disease but only modestly and only in those at high risk.

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.

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.

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.

Lesions caused by herpes simplex virus may appear in various clinical stages. They are usually the result of an HSV-1 infection and they may appear on the face and neck. They start as fluid-filled blisters which eventually erupt into small painful ulcers.

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.

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).

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

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

Tinea corporis is a type of dermatophytosis, caused by Trichophyton or Microsporum. The disease is highly contagious and rapidly spreads to all the areas of the body, including the glabrous skin. It produces an erythematous itchy skin rash with a central area of clearance surrounded by raised scaly borders. Lesions can appear as concentric circles that overlap, referred to as tinea imbricate.

Hypopigmentation is a side-effect that is more likely to be due to eczema rather than topical steroids therapy.All the options provided are potential side-effects of topical steroid therapy. They are observed when the potency of the steroid used is too high, or the amount of drug used is too much.. FTU or fingertip unit application is what is recommended, with caution, in delicate areas such as the face. Hypopigmentation can occur in eczema and is a post-inflammatory response, in contrast to the total depigmentation which is seen in vitiligo. Chronic eczema causes lichenification of skin, where the epidermis is thickened, and not skin atrophy.

Capillary haemangiomas are one of the most common benign tumours of infancy. They are benign endothelial cell neoplasms that are typically absent at birth and characteristically have rapid growth in infancy with spontaneous involution later in life. This is in contrast to another known group of childhood vascular anomalies, vascular malformations. Vascular malformations, such as lymphangiomas and arteriovenous malformations, are present at birth and are characterized by very slow growth with persistence into adult life. The indications for treatment can be divided into systemic, ophthalmic, and dermatologic reasons. Systemic reasons for intervention include congestive heart failure, thrombocytopenia, haemolytic anaemia, and nasopharyngeal obstruction. Ophthalmic indications for intervention include occlusion of the visual axis, optic nerve compression, severe proptosis, and anisometropia. Dermatologic indications for intervention include maceration and erosion of the epidermis, infection, and cosmetic disfigurement.The first-line treatment of capillary haemangiomas is simple observation. Since most of these lesions regress on their own, there is no need to intervene unless one of the above criteria is met.

External oblique forms the outermost muscle of the three muscles comprising the anterolateral aspect of the abdominal wall. Its aponeurosis comprises the anterior wall of the inguinal canal.

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.

Eczema herpeticum is a form of Kaposi varicelliform eruption, characterized by extensive vesicular skin eruptions that arise from a pre-existing skin condition, usually atopic dermatitis. The most common pathogen is the herpes simplex virus type 1, which has a higher propensity of attacking the epidermis already damaged by atopic dermatitis. The incubation period of the illness is 5-14 days. The eruption is initially small, monomorphic, dome-shaped papulovesicles that rupture to form tiny punched-out ulcers. It is diagnosed by taking viral swabs for culture.

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.

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.

Certain infections and medications cause characteristic skin lesions, which are the result of hypersensitivity reactions to these agents. A skin rash characterized by the eruption of macules, papules, and target-like circular lesions is referred to as erythema multiforme. 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 with a propensity for distal extremities. The most common infectious cause is the infection with herpes simplex virus 1 and 2 to a lesser extent. Other notable infectious causes of erythema multiforme include Mycoplasma pneumoniae, cytomegalovirus, HIV, hepatitis c virus, varicella zoster virus, adenovirus, and some fungal infections. Norovirus infection has not been implicated in the aetiology of erythema multiforme.

Alopecia is a scalp condition characterized by either overall baldness or patches of hair loss over the head. It can be broadly classified as scarring alopecia and non-scarring alopecia. Non-scarring is the most common type and is seen in various conditions like nutritional deficiencies, alopecia areata, hypothyroidism, tinea capitis, and SLE. Scarring alopecia is commonly seen in cases of discoid lupus erythematosus, which is a common cause of widespread inflammatory and scarring lesions all over the body and scalp.

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.

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.

Impetigo appears more commonly on the face than other exposed areas like the limbs. Its blisters are clustered and may have a fluid discharge.

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.

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.

“Tinea incognito” is a term used to describe a tinea infection modified by topical steroids. It is caused by prolonged use of topical steroids, sometimes prescribed as a result of incorrect diagnosis. Topical steroids suppress the local immune response and allow the fungus to grow easily. As a result, the fungal infection may take on the bizarre appearance seen in this patient.The diagnosis of tinea incognito is simple to confirm by microscopic visualization of branching hyphae and spores typical of dermatophytes in a potassium hydroxide preparation.Treatment of tinea incognito requires cessation of all topical steroid use and implementation of specific antifungal treatment. A low-potency corticosteroid may be used briefly to avoid the flare often associated with abrupt cessation of a potent steroid. Patients should be warned of this possibility so they do not reinstitute use of topical steroids on their own.

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

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.