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.

Melanoma, a highly malignant tumour arising from melanocytes, is the most common life-threatening dermatological disease. Risk factors include UV radiation exposure, particularly in light-skinned individuals that are easily sunburned, increasing age, family history, and immunosuppression. Lesions that are suspicious for melanoma should be excised with complete margins. Radical excision is not routinely undertaken for diagnostic purposes and therefore if subsequent histopathological assessment determines that the lesion is a melanoma a re-excision of margins may be required.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 – 3cm

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.

It is recommended that a woman wait one month after stopping isotretinoin before trying to become pregnant. Usually, isotretinoin is no longer found in a woman’s blood 4-5 days after the last dose and most of its by-products should be gone within 10 days after the last dose.

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.

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 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 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.

Psoriasis is an autoimmune dermatological condition that causes cells of the epidermal layer to rapidly develop, leading to itchy scaly plaques. Phototherapy with UV radiation has emerged as a new treatment for difficult to treat psoriasis. The therapy works by inducing epidermal cell apoptosis by DNA damage through the formation of pyrimidine dimerization, disrupting the cell cycle. This slows the rapid proliferation of cells.

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.

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.

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.

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

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 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.

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 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.

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.

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.

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

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

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.

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 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.

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.

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

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. It produces an itchy rash with a central area of clearance surrounded by raised scaly borders. Diagnosis can be made by skin examination. All other mentioned conditions do not affect the palms and soles.

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.

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

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.