Hypopigmentation refers to a decrease in the amount of the pigment melanin in the skin, which leads to an abnormally lighter skin tone. Hypopigmentation can be generalized or localized. Generalized hypopigmentation occurs in albinism or can be ethnicity related. Causes of localized hypopigmentation include Incontinentia pigmenti, Lichen planus, Tuberous sclerosis, Piebaldism, vitiligo, and leprosy. Celiac disease is not associated with hypopigmentation.

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.

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.

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.

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 cafe-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

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.

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.

Itchy skin conditions include:Allergy & anaphylaxisAthletes footAtopic dermatitisContact dermatitisDrug allergyErythema multiformeFolliculitisImpetigoInsect bites, stings, infestationsKawasaki diseaseLichen planusNummular eczemaPityriasis roseaPsoriasisScabiesTinea corporisToxic epidermal necrolysisUrticariaVaricellaViral exanthemNote: Miliaria rubra is itchy, miliaria profunda usually isn’t.

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 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 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.

Pityriasis amiantacea is a reaction pattern rather than a specific diagnosis. Common conditions that may present with pityriasis amiantacea include:Scalp psoriasisSeborrhoeic dermatitisAtopic dermatitisTinea capitis.Head lice and lichen simplex should also be considered.When no underlying cause is found, the condition is often called idiopathic pityriasis amiantacea.

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.

Henoch-Schonlein purpura (HSP), also known as IgA vasculitis, is a disease of the skin, mucous membranes, and sometimes other organs that most commonly affects children. In the skin, the disease causes palpable purpura (small, raised areas of bleeding underneath the skin), often with joint pain and abdominal pain. It is an acute immunoglobulin A (IgA)-mediated disorder. The tetrad of purpura, arthritis, kidney inflammation, and abdominal pain is often observed.

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.

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.

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.

Cafe-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 IMcCune-Albright syndromeLegius syndromeTuberous sclerosisFanconi anaemiaIdiopathicAtaxia-telangiectasiaBasal cell nevus syndromeBenign congenital skin lesionBloom syndromeChediak-Higashi syndromeCongenital nevusGaucher diseaseHunter syndromeMaffucci syndromeMultiple mucosal neuroma syndromeNoonan syndromePulmonary StenosisSilver-Russell syndromeWatson syndromeWiskott-Aldrich syndrome

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.

Skin conditions resulting from excessive epidermal proliferation or inflammation, leading to a production of excessive scales, are referred to as papulosquamous disorders. These disorders can be generalized and localized. Localized causes of scaly lesions include tinea corporis, tinea cruris, tinea pedis, seborrheic dermatitis, psoriasis, pityriasis Versicolor, pityriasis alba, DLE, ichthyosis including Netherton syndrome (a severe form of ichthyosis which is autosomal recessive), and pellagra. Generalized causes include guttate psoriasis and pityriasis rosacea. Hand, foot, and mouth disease is a contagious viral illness that causes blisters in the mouth and on the extremities.

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.

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.

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.

According to the Gell and Coombs classification of hypersensitivity reactions, the scenario provided is a type 4 (delayed) reaction.These reactions are mediated by T lymphocytes and cause contact dermatitis. Nickel, commonly found in cheap jewellery, is a common cause of contact dermatitis.Note:There are two main types of contact dermatitis:- Irritant contact dermatitis: It is a common, non-allergic reaction due to weak acids or alkalis (e.g. detergents). These are often seen on the hands. They present typically with erythema, and rarely, crusting and vesicles.- Allergic contact dermatitis: These are type IV hypersensitivity reactions and are often seen on the head following hair dyes.They typically present as acute weeping eczema which predominately affects the margins of the hairline rather than the hairy scalp itself. Treatment is usually with a potent topical steroid.Other options:- Allergic rhinitis is an example of a type 1 (immediate) reaction. It is an IgE mediated. It is a hypersensitivity to a previously innocuous substance.- Type 2 reactions are mediated by IgG and IgM, which binds to a cell, causing cell death. Goodpasture syndrome is an example of a type 2 hypersensitivity reaction.- Immune complexes mediate type 3 reactions. Rheumatoid arthritis is an example of a type 3 hypersensitivity reaction.

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.

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.

Gilbert’s syndrome is an autosomal recessive condition that results from defective bilirubin conjugation due to a deficiency of UDP glucuronyl transferase – 1. The prevalence is approximately 1-2% in the general population.The clinical presentation of Gilbert’s syndrome include:- Unconjugated hyperbilinaemia- Jaundice can occur during an intercurrent illnessManagement:Blood investigations usually reveal a rise in bilirubin following prolonged fasting or intravenous nicotinic acid.No treatment required for these patients.Other options:- CYP2C9 deficiency causes reduced warfarin metabolism, and subsequent enhanced drug effects. – Pancreatic disease, cholestasis, excessive alcohol consumption and certain drugs are common causes of raised GGT levels- Defective hepatocyte excretion of conjugated bilirubin is related to the pathophysiology of Dubin-Johnson syndrome- Reduced CYP2C19 levels can lead to the disordered metabolism of clopidogrel and other drugs such as proton-pump inhibitors, anticonvulsants and sedatives.

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.

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.

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.

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.

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.

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.

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.

Tinea incognitoť 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.

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.

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.

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.

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.