Common Skin Infections and Their Causes

Skin infections can be caused by a variety of pathogens, including viruses, fungi, and bacteria. Here are some common skin infections and their causes:

Varicella-zoster virus: This virus causes shingles, which is a reactivation of the virus that has been dormant in the dorsal root ganglia after the patient’s initial exposure to the virus in the form of chickenpox. A live attenuated vaccine is now available that is effective in preventing shingles.

Herpes simplex virus infection: This virus can occasionally appear in a dermatomal distribution, mimicking shingles. It presents with erythema and vesicles, but the area of skin involved is usually much less than in shingles and pain is not as prominent.

Malassezia furfur: This fungus causes tinea versicolor, a common benign, superficial cutaneous fungal infection characterized by hypopigmented or hyperpigmented macules and patches on the chest and back.

Trichophyton verrucosum: This dermatophyte fungus of animal origin (zoophilic) causes a kerion, a severely painful inflammatory reaction with deep suppurative lesions on the scalp or beard area.

Staphylococcus aureus: This bacterium causes impetigo, sycosis, ecthyma, and boils.

Common Skin Infections and Their Causes

Understanding Scabies Infestation

Scabies infestation is a skin condition caused by the Sarcoptes scabiei mite. It is commonly transmitted through close contact and is prevalent in nursing homes and other institutions. The primary symptom of scabies is severe itching, and if present, burrows (linear crusted lesions) and penile papules are highly suggestive. The condition typically affects the web-spaces and around the nipples, with scalp involvement only occurring in young babies and debilitated adults. Excoriations are also common.

The treatment for scabies usually involves the use of permethrin, and close contacts should be treated simultaneously. Atopic eczema is unlikely to present at this age, and chronic kidney disease and diabetes are associated with several skin conditions but do not typically cause pruritus. Iron-deficiency anaemia may cause pruritus, but it is rarely as severe as scabies.

Skin Conditions: Lichen Planus, Erythema Multiforme, Tinea Versicolour, Psoriasis, and Ringworm

Lichen planus is an inflammatory skin condition that affects both cutaneous and mucosal surfaces. It is characterized by flat-topped plaques and papules with a purple hue and white striae. Topical steroids and immunomodulators are used to treat it, as it can increase the risk of squamous cell carcinoma if left untreated.

Erythema multiforme is a skin condition that presents with targetoid lesions with a central depression, usually starting on the acral extensor surfaces. It can be caused by medications, infections, or underlying conditions such as sarcoidosis and non-Hodgkin’s lymphoma.

Tinea versicolour, also known as pityriasis versicolor, is a fungal skin infection that causes pale or dark patches on the arms, neck, and trunk. It does not involve mucosal surfaces.

Psoriasis is an autoimmune chronic skin condition that presents with erythematous plaques with overlying grey scale on the extensor surfaces of extremities. It is not associated with intra-oral mucosal lesions.

Ringworm, also known as tinea corporis, is a fungal skin infection that causes erythematosus, scaly patches on the skin surface of the trunk, back, and extremities. It is not usually seen on the scalp, groin, palms, and soles. The patches progressively enlarge and worsen, and can lead to the formation of pustules or vesicles. Following central resolution, the lesions can remain annular.

Common Skin Infections and their Causes

Acne vulgaris is a prevalent skin condition among adolescents and young adults, particularly men. Hormonal changes stimulate the sebaceous glands to produce more sebum, leading to the formation of open comedones, which are inflamed follicles with a central dark plug of keratin. Propionibacterium acnes is responsible for breaking down complex lipids in sebum into free fatty acids, which cause inflammation of hair follicles. Treatment with antibiotics and 13-cis-retinoic acid can alleviate the symptoms of acne vulgaris.

Molluscum contagiosum is caused by the poxvirus, which leads to epidermal hyperplasia and ellipsoid molluscum bodies in the stratum corneum.

Impetigo is a bacterial infection of the skin caused by Staphylococcus aureus. It is highly contagious and often affects healthy children. The infection starts as a reddened macule and progresses to multiple serum-filled pustules that rupture and form a yellowish crust.

Papillomavirus causes warts or verrucae, which are common on the hands. They appear as several papules with a rough, irregular surface.

Tinea versicolor is caused by Malassezia furfur, a fungus that causes superficial fungal infections in the skin. Other forms of tinea are also caused by fungal infections.

Understanding Pemphigus Vulgaris: An Autoimmune Blistering Condition

Pemphigus vulgaris is a blistering condition that primarily affects middle-aged individuals. It is caused by IgG autoantibodies against desmosomal components, specifically desmogleins 1 and 3, in the superficial layers of the skin. This results in flaccid blisters that easily rupture, leading to erosions and scarring. The oral mucosa is often affected early on, and Nikolsky’s sign is positive. Immunofluorescence reveals intra-epidermal circular deposits, and antibodies against desmosomes are typically positive. Treatment involves high-dose steroids and may require life-long maintenance doses. In contrast, bullous pemphigoid, which affects older individuals, is characterized by antibodies against hemidesmosomes in the deeper basement membrane of the skin, resulting in tense, firm blisters that do not rupture easily. Psoriasis, alopecia, and HIV are not linked to pemphigus vulgaris.

Skin Conditions Associated with Various Diseases

Pyoderma gangrenosum is a skin condition associated with Crohn’s disease. It is diagnosed based on clinical history and examination, and treatment options include topical or systemic steroid therapy. Coeliac disease is not associated with pyoderma gangrenosum, but is linked to dermatitis herpetiformis, which causes itchy papules on the scalp, shoulders, buttocks, or knees. Pretibial myxoedema is a skin condition associated with Grave’s disease, characterized by waxy, discolored induration on the Pretibial areas. SLE is not associated with pyoderma gangrenosum, but is linked to a facial butterfly rash. T1DM is not associated with pyoderma gangrenosum, but is linked to necrobiosis lipoidica and granuloma annulare, which cause tender patches and discolored plaques, respectively.

Cavernous Haemangiomas and Alopecia Areata: Conditions and Treatment Options

Cavernous haemangiomas are benign growths that typically appear within the first two weeks of life. They are usually found on the face, neck, or trunk and are well-defined and lobulated. Surgical excision is not recommended, but treatment may be necessary if the growths inhibit normal development, such as obstructing vision in one eye. Treatment options include systemic or local steroids, sclerosants, interferon, or laser treatment.

Alopecia areata is an autoimmune condition that causes hair loss in discrete areas. Treatment options include cortisone injections into the affected areas and the use of topical cortisone creams. It is important to note that both conditions require medical attention and treatment to prevent further complications. With proper care and treatment, individuals with cavernous haemangiomas and alopecia areata can manage their conditions and improve their quality of life.

Genetic Tumor Disorders and Their Skin Manifestations

There are several genetic disorders that predispose individuals to the formation of tumors, including those in the nervous system. These disorders can also have distinct skin manifestations that aid in their diagnosis.

Tuberous Sclerosis: This rare multisystem genetic disease is caused by abnormalities on chromosome 9 and leads to the formation of benign tumors (hamartomas) in various organs, including the brain, eyes, skin, kidney, and heart. Skin problems associated with tuberous sclerosis include periungual fibromas, adenoma sebaceum, ‘ash leaf’ hypomelanotic macules, café-au-lait patches, subcutaneous nodules, and shagreen patches. Neurological symptoms such as seizures, developmental delay, behavioral problems, and learning difficulties can also occur.

Neurofibromatosis I: This inherited condition causes tumors (neurofibromas) to grow within the nervous system and is characterized by café-au-lait spots on the skin.

Von Hippel-Lindau Disease: This inherited tumor disorder is caused by a mutation in a tumor suppressor gene on chromosome 3 and is commonly associated with angiomatosis, hemangioblastomas, and pheochromocytomas.

Neurofibromatosis II: This disorder presents with bilateral hearing loss due to the development of bilateral acoustic neuromas.

Sturge-Weber Syndrome: This congenital disorder is identified by a port-wine stain on the forehead, scalp, or around the eye.

Dermatological Conditions and Their Relationship to Erythroderma

Erythroderma is a condition that causes inflammation, redness, and scaling of over 90% of the skin surface. It can be caused by various dermatological conditions, including eczema, psoriasis, cutaneous T cell lymphoma, drug reactions, blistering conditions, and pityriasis rubra pilaris. Complications of erythroderma include hypothermia, dehydration, infection, and high-output heart failure. Treatment involves identifying and stopping any causative drugs, nursing in a warm room, and systemic steroids.

Livedo reticularis is another skin condition that causes a mottled discoloration of the skin in a reticular pattern due to a disturbance of blood flow to the skin. However, it does not cause erythroderma.

Lichen planus is a chronic inflammatory skin condition that presents with a pruritic, papular eruption characterized by its violaceous color and polygonal shape, sometimes with a fine scale. It does not commonly cause erythroderma.

Norwegian scabies is a severe form of scabies caused by a mite infestation, but it does not cause erythroderma.

Pityriasis rosea is a viral rash characterized by a herald patch followed by smaller oval, red patches located on the torso. It does not cause erythroderma.

Common Skin Infections and Their Causes

Molluscum contagiosum is a viral infection that spreads through direct contact and causes pink papules with a central umbilicus. The lesions contain cheese-like material and can be treated with cryotherapy or imiquimod.

Cellulitis is a bacterial infection that affects the lower dermis and subcutaneous tissue, causing red, swollen, and painful skin. It is commonly caused by Streptococcus pyogenes and Staphylococcus aureus.

Folliculitis is an inflammation of the hair follicles, often caused by staphylococcal infections.

Impetigo is a bacterial infection that results in pustules and honey-colored, crusted erosions. It is commonly caused by S. aureus.

Necrotizing fasciitis is a severe bacterial infection that affects soft tissue and fascia. The bacteria release toxins and enzymes that lead to thrombosis and destruction of soft tissue and fascia. Bacterial causes include S. aureus and Clostridium perfringens, among others.

Overview of Common Skin Infections and Their Causes

Management of Basal Cell Carcinoma: Referral and Treatment Options

Basal cell carcinomas (BCCs) are slow-growing skin cancers that require prompt referral to a dermatologist for assessment and management. While not urgent, referral should be routine to ensure timely treatment and prevent further growth and potential complications. Treatment options may include surgical excision, curettage and cautery, radiotherapy, or cryotherapy, depending on the size and location of the lesion.

5-fluorouracil cream and diclofenac topical gel are not recommended for the treatment of BCCs but may be used for pre-malignant lesions such as solar keratoses. Referral to oncology for radiotherapy may be considered, but dermatology should be consulted first to explore less invasive treatment options.

A watch-and-wait approach is not recommended for suspected BCCs, as delaying referral can lead to more extensive treatments and potential complications. All lesions suspected of malignancy should be referred to a specialist for further assessment and definitive treatment.

Autoantibodies and Skin Disorders: Understanding the Role of Desmoglein, Bullous Pemphigoid Antigen, Collagen Type XVIII, Keratin, and Desmoplakin

Skin disorders can be caused by various factors, including autoimmune reactions. In particular, autoantibodies targeting specific proteins have been linked to several skin conditions. Here are some of the key proteins involved in these disorders:

Desmoglein: This protein is targeted by autoantibodies in about 80% of pemphigus cases, specifically in pemphigus vulgaris. The autoantibodies disrupt desmosomes, leading to blister formation above the stratum basale.

Bullous pemphigoid antigen and collagen type XVIII: These proteins are associated with bullous pemphigoid, which is characterized by autoimmune disruption of the hemidesmosome. This structure attaches the basal surface of cells in the stratum basale to the underlying epidermal basement membrane.

Keratin: Mutations in genes encoding keratin have been linked to epidermolysis bullosa, a disorder that causes blistering and skin fragility.

Desmoplakin: This intracellular protein links keratin intermediate filaments to desmosomes, but it is not directly involved in the pathogenesis of pemphigus vulgaris.

Understanding the role of these proteins in skin disorders can help researchers develop better treatments and therapies for these conditions.

The Skin and its Glands: A Brief Overview

The skin is the largest organ of the human body and is responsible for protecting the body from external factors such as bacteria, viruses, and physical trauma. It is composed of several layers, with the outermost layer being the stratum corneum, a keratinised squamous epithelial layer.

One of the most common skin conditions is acne, which is caused by the sebaceous glands associated with hair follicles secreting sebum and plugging the hair follicle. If left untreated, acne can cause scars or pock marks after the lesions heal. Treatment options include benzoyl peroxide, tetracycline antibiotics, or retinoic acid.

Apocrine glands secrete a viscous, milky substance and are found in the axillary and genital regions. They become active during puberty and are associated with a characteristic foul odor due to bacteria consuming the fluid expressed from these glands.

Eccrine glands are sweat glands and are found all over the body. They play a crucial role in regulating body temperature and eliminating waste products.

Hemidesmosomes connect basal cells to the underlying basal membrane. Antibodies to hemidesmosomes can lead to the formation of bullous pemphigoid, a rare autoimmune disorder that causes blistering of the skin and mucous membranes.

Understanding the different glands and layers of the skin can help in the diagnosis and treatment of various skin conditions.

Understanding Scabies: Symptoms and Characteristics

Scabies is a skin condition caused by the infestation of the mite Sarcoptes scabiei, variety hominis. The female mite burrows into the skin, creating characteristic lesions known as burrows. However, the absence of burrows does not rule out a diagnosis of scabies. Other symptoms include erythema, or redness and scaling of the skin, and excoriations, or skin abrasions caused by scratching. In severe cases, crusting patches may develop, particularly in crusted scabies, a highly contagious variant of the condition. Prurigo nodules, or small bumps on the skin, may also occur in scabies, especially in young children. It is important to seek medical attention if you suspect you have scabies, as prompt treatment can prevent the spread of the condition.

Managing Eczema in Children: Treatment Options and Referral Considerations

When a child presents with eczema, the first step is often to use emollient cream to manage the symptoms. However, if the eczema persists or worsens, a topical corticosteroid cream may be necessary. It is important to use this sparingly and in conjunction with emollients. While oral corticosteroids may be considered in severe cases, they should be used with caution and ideally under the guidance of a dermatologist. Emollient ointments may also be helpful, but a short course of topical corticosteroids is often more effective for managing flare-ups. If symptoms continue to worsen despite treatment, referral to a dermatology clinic may be necessary. Watchful waiting is not appropriate in this situation.

Livedo Reticularis

Livedo reticularis is a skin condition characterized by a net-like pattern of blue or purple discoloration on the skin. This occurs due to the dilation of capillary blood vessels and the stagnation of blood within these vessels. The condition is more pronounced in cold weather and is commonly found on the legs, arms, and trunk.

Livedo reticularis can be idiopathic, meaning it has no known cause, or it can be secondary to other conditions such as malignancy, vasculitis, SLE, or cholesterol embolization. The condition is caused by the accumulation of blood in the capillaries, which leads to the discoloration of the skin.

In summary, livedo reticularis is a skin condition that causes a net-like pattern of blue or purple discoloration on the skin. It is caused by the accumulation of blood in the capillaries and can be idiopathic or secondary to other conditions. The condition is more pronounced in cold weather and is commonly found on the legs, arms, and trunk.

Neurofibromatosis Type 1 and Type 2

Neurofibromatosis is a genetic disorder that affects the 17th chromosome and is inherited in an autosomal dominant manner. There are two types of neurofibromatosis: type 1 and type 2. Type 1 is also known as von Recklinghausen’s disease and is characterized by flat, light-brown skin lesions called café au lait spots, axillary freckling, small purple-colored lesions called dermal neurofibromas, nodular neurofibromas that can cause paraesthesia when compressed, and Lisch nodules on the iris. Complications of type 1 neurofibromatosis include nerve compression, phaeochromocytoma, mild learning disability, and epilepsy.

Type 2 neurofibromatosis is much rarer than type 1 and also demonstrates autosomal dominant inheritance. In addition to café au lait spots, individuals with type 2 may also develop vestibular schwannomas (acoustic neuromas) and premature cataracts. It is important to note that while both types of neurofibromatosis share some similarities, they also have distinct differences in their clinical presentation and associated complications. these differences can aid in accurate diagnosis and management of these conditions.

The 7-Point Checklist for Assessing Pigmented Lesions

The 7-point checklist is a tool used to assess pigmented lesions for potential malignancy. Major features, such as a change in size, irregular shape or border, and irregular color, score 2 points each. Minor features, including a largest diameter of 7 mm or more, inflammation, oozing or crusting of the lesion, and change in sensation (including itch), score 1 point each. The weighted 7-point checklist is recommended by the National Institute for Health and Care Excellence (NICE) for use in General Practice. Lesions scoring three points or more should be referred urgently to Dermatology. Malignant melanomas can present with the development of a new mole or a change in an existing mole. The features highlighted in the 7-point checklist should be ascertained in the history to determine how urgently a mole needs to be referred to exclude malignancy.

Differences and Similarities between Acne and Rosacea

Acne vulgaris and rosacea are two common skin conditions that affect the face. While they share some similarities, they also have distinct differences.

Acne vulgaris is characterized by a mixture of comedones, papules, pustules, nodules, and cysts. Comedones are formed when the cells lining the sebaceous duct proliferate excessively and block the duct. Open comedones are blackheads, while closed comedones are whiteheads. Other types of comedones include giant comedones and solar comedones. Acne vulgaris usually starts in puberty and can continue into adulthood.

On the other hand, rosacea is a chronic or intermittent rash that affects the central face. It is characterized by blushing or flushing and persistent redness and telangiectasia. Telangiectasias are small, dilated blood vessels that appear as red lines on the skin. Papules and pustules may also develop, and the skin may be dry and flaky. The nose may have prominent pores due to sebaceous gland hyperplasia.

While both acne and rosacea can present with papules, pustules, and crusting, comedones are a characteristic feature of acne and are not present in rosacea. Additionally, acne vulgaris usually starts in puberty and is more common in younger individuals, while rosacea typically affects those aged 30-60.

In summary, while acne and rosacea share some similarities in their presentation, they also have distinct differences that can help differentiate between the two conditions.

Pemphigoid: A Skin Condition Caused by Furosemide

Pemphigoid is a skin condition that typically affects elderly individuals, presenting as tense blisters on the arms and legs. The use of furosemide, a diuretic, is a common cause of this condition. While other diuretics can also cause pemphigoid, it is a rarer occurrence. A positive immunofluorescence test confirms the diagnosis, and treatment with steroids is usually successful.

It is important to differentiate pemphigoid from pemphigus, which presents in younger age groups and causes flaccid blisters that easily erupt, leading to widespread lesions. Overall, recognizing the signs and symptoms of pemphigoid and identifying its underlying cause can lead to effective treatment and management of this skin condition.

Understanding Rodent Ulcers: Characteristics and Treatment Options

Rodent ulcers, also known as basal cell carcinomas, are malignant skin lesions that commonly occur on the upper part of the face and ears, particularly in sun-exposed areas. They present as a pearly white nodule with telangiectasia and may ulcerate with a rolled edge as they enlarge. Unlike squamous cell carcinomas, rodent ulcers rarely metastasize via the bloodstream. Instead, they are malignant through local invasion, causing significant tissue damage by eroding into local tissue.

Treatment options for rodent ulcers depend on the depth of the ulcer. Surgical excision with an excision margin of 3-5 mm, Mohs micrographic surgery, radiotherapy, and curettage, cautery, and cryotherapy are all viable options. Mohs micrographic surgery is particularly useful for lesions on the face where wide excision is not appropriate.

In contrast, squamous cell carcinomas are malignant skin lesions that usually present as an ulcerated lesion with hard and raised edges in sun-exposed areas. They can occur on the lips in smokers and can metastasize, although spread is typically local. Treatment for squamous cell carcinomas involves excision and radiotherapy.

In summary, understanding the characteristics and treatment options for rodent ulcers is crucial for effective management of this type of skin cancer.

Treatment for Fungal Nail Infection

Fungal nail infection is a common condition that affects many adults. If self-care measures and topical treatments are not successful or appropriate, treatment with an oral antifungal agent should be offered. The first-line treatment recommended is Terbinafine, which is effective against both dermatophytes and Candida species. On the other hand, ‘-azoles’ such as fluconazole do not have as much efficacy against dermatophytes. It is important to seek medical advice and follow the recommended treatment plan to effectively manage fungal nail infection. For further information, resources such as CKS Fungal nail infections, GP Notebook, and Patient.info can be consulted. The British Association of Dermatologists also provides guidelines for the treatment of onychomycosis.

Understanding Topical Steroid Creams for Atopic Eczema Treatment

Atopic eczema is a common skin condition that can be managed with the use of topical steroid creams. These creams come in different potencies, and it is important to use the least potent effective cream for children to avoid side effects. The first step in treatment is emollients such as aqueous cream, followed by mild potency hydrocortisone 1-2.5%. If there is no response, a moderately potent cream like Eumovate may be used. Potent creams like Betnovate and very potent creams like Dermovate are not appropriate next steps in management. Trimovate is a moderate steroid cream with antimicrobial effect. The goal is to achieve control of eczema and step down the ladder of potency until maintenance is achieved on the least potent agent. Understanding the different types of topical steroid creams can help in the effective management of atopic eczema.

Skin Conditions Associated with Various Diseases

Pyoderma gangrenosum is a skin condition characterized by a painful ulcer that rapidly enlarges. It is commonly associated with inflammatory bowel disease, hepatitis, rheumatoid arthritis, and certain types of leukemia. However, it is not commonly associated with HIV infection or coeliac disease. Dermatitis herpetiformis is a skin condition associated with coeliac disease, while patients with rheumatoid arthritis are at higher risk of developing pyoderma gangrenosum compared to those with osteoarthritis. Haematological malignancies commonly associated with pyoderma gangrenosum include acute myeloid leukemia and hairy cell leukemia, while cutaneous lesions in multiple myeloma are uncommon.

Bullous Pemphigoid

Bullous pemphigoid is a skin condition that is characterized by the presence of tense bullae, which are filled with clear fluid and appear on normal or erythematosus skin. Unlike pemphigus vulgaris, which causes blisters at the dermal-epidermal junction, bullous pemphigoid causes blistering at the subepidermal level, resulting in the formation of tense blisters. In contrast, pemphigus vulgaris causes thin-walled and fragile blisters that are rarely intact.

To differentiate bullous pemphigoid from other skin conditions, such as pemphigus vulgaris, a skin biopsy for routine and direct immunofluorescence is necessary. This test helps to identify the presence of linear basement membrane zone deposition of immunoglobulin and complement, which are of the IgG type.

In summary, bullous pemphigoid is a skin condition that causes the formation of tense bullae on normal or erythematosus skin. It is important to differentiate it from other skin conditions, such as pemphigus vulgaris, through a skin biopsy for routine and direct immunofluorescence.

The patient is presenting with erythema nodosum, which may have an unknown cause or could be related to their extensive travel history. While a skin biopsy may provide a definitive diagnosis, the best initial investigation is a chest X-ray to rule out tuberculosis and sarcoidosis. A blood film is not necessary as there is no indication of malaria. An ultrasound of the abdomen is not useful in this case, as the skin lesions are the primary concern. Stool microbiology is not necessary as there is no mention of diarrhea. While a skin biopsy may provide information on the lesions themselves, it does not aid in identifying the underlying cause.

Management of Erythroderma in an Elderly Patient Living Alone

Erythroderma is a dermatological emergency that requires urgent treatment. In elderly patients who are systemically unwell and live alone, urgent admission to the hospital is necessary. This is the case for an 86-year-old man with a history of psoriasis who presents with erythroderma. The patient needs to be managed in the hospital due to the high risk of infection and dehydration. Topical emollients and steroids are essential in the management of erythroderma, but this patient requires intravenous fluids and close monitoring. Oral antibiotics are not indicated in the absence of features of infection. A topical steroid with a vitamin D analogue would be appropriate for a patient with psoriasis, but urgent assessment by Dermatology in an inpatient setting is necessary. An urgent outpatient Dermatology appointment is not appropriate for an elderly patient with abnormal observations and living alone.

Skin Disorders: Pemphigus Vulgaris, Bullous Pemphigoid, Dermatitis Herpetiformis, Epidermolysis Bullosa, and Tuberous Sclerosis

Skin disorders can manifest in various ways, including blistering and erosions on the skin and/or mucous membranes. Pemphigus vulgaris is an autoimmune disease that causes blistering and erosions on the skin and mucous membranes, with IgG autoantibodies to desmoglein 3 being a key characteristic. In contrast, bullous pemphigoid involves sub-epidermal splitting and tense blisters that are less easily ruptured. Dermatitis herpetiformis is characterised by intensely pruritic blisters on specific areas of the body, often associated with coeliac disease. Epidermolysis bullosa is a rare inherited disorder that causes fragile skin, while tuberous sclerosis is not associated with blistering. Diagnosis and treatment vary depending on the specific disorder.

Scabies: Causes, Symptoms, and Treatment

Scabies is a skin infestation caused by the microscopic mite Sarcoptes scabiei. It is a common condition that affects people of all races and social classes worldwide. The infestation spreads rapidly in crowded conditions where there is frequent skin-to-skin contact between people, such as in hospitals, institutions, child-care facilities, and nursing homes. Scabies can be transmitted through direct, prolonged, skin-to-skin contact with an infested person, and it can also spread by sharing clothing, towels, and bedding.

The symptoms of scabies include papular-like irritations, burrows, or rash of the skin, particularly in the webbing between the fingers, skin folds on the wrist, elbow, or knee, the penis, the breast, or shoulder blades. The condition is highly contagious and can easily spread to sexual partners and household members. However, a quick handshake or hug is usually not enough to spread the infestation.

Fortunately, there are several treatments available for scabies, including permethrin ointment, benzyl benzoate, and oral ivermectin for resistant cases. Antihistamines and calamine lotion may also be used to alleviate itching.

Management of Severe Extensive Psoriasis: Consideration of Anti-TNF Alpha Therapy

Psoriasis is a chronic inflammatory skin condition that is managed in a stepwise manner, as per the National Institute of Health Care and Excellence (NICE) guidelines. For patients with extensive psoriasis who have failed topical therapy, phototherapy, and systemic agents such as methotrexate, acitretin, and ciclosporin, or where these are not tolerated and/or contraindicated, the next step in management is to trial an anti-tumour necrosis factor (TNF) alpha, such as infliximab, etanercept, or adalimumab, given by injection.

While on anti-TNF alpha therapy, patients are at an increased risk of pneumococcal and seasonal influenzae, and should receive vaccination against these illnesses. Live vaccines should be avoided.

Repeating a further course of phototherapy may not be the most appropriate answer for patients who have already failed systemic therapy and previously showed only minimal response to phototherapy. Hydroxychloroquine is not commonly used in the management of plaque psoriasis, and rituximab is not indicated for psoriasis.

Topical tacrolimus may be used in the management of psoriasis affecting the face or flexural regions, but for patients with severe extensive psoriasis on the trunk, arms, and buttocks who have already tried and failed management with oral regimes and phototherapy, it is unlikely to be of benefit. If it has not already been used, it would not be unreasonable to trial tacrolimus for a short period. However, the next most appropriate step in management is an anti-TNF alpha.

In summary, for patients with severe extensive psoriasis who have failed previous therapies, consideration of anti-TNF alpha therapy is the next step in management, with appropriate vaccination and monitoring for potential adverse effects.