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.

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.

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.

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.

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.

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.

The most probable diagnosis for this patient, according to the clinical scenario provided is tuberous sclerosis. It 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 to be associated with this condition. The condition has a variable expression and penetrance and is further characterised by:- Seizures (usually infantile spasms)- Developmental delay- Facial/cutaneous angiofibromas (adenoma sebaceum)- Periungual fibromas (pink projections from the nail folds)- Shagreen patches (leathery thickenings of the skin usually on the back) – Ash leaf macules (areas of depigmentation that become visible under a Wood’s light)- Fundoscopy may reveal white streaks along the fundal vessels.

Eczema is an immune-mediated inflammatory condition of the skin characterized by intense pruritis and scaly rashes over the body. The impact of the disease can be measured by using certain scales, which include the Dermatitis Family Impact (DFI) Questionnaire, infant’s Dermatitis Quality of Life Index, Patient-oriented Eczema Measure, and Children’s Dermatology Life Quality Index among many others. Eczema severity questionnaire is not a recognized scale to determine eczema impact.

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 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.