Common Skin Conditions: Symptoms and Treatment Options

Seborrhoeic Dermatitis: This condition is caused by a hypersensitivity reaction to a superficial fungal infection, Malassezia furfur. It typically affects the scalp and face, presenting as yellow papules and scaling plaques with underlying erythema. Treatment involves topical steroid and anti-fungal drugs.

Contact Dermatitis: Hypersensitivity reactions to substances like latex, jewellery, soap, and detergents can cause pruritic erythematous rashes with papulo-vesicular lesions at the site of contact.

Atopic Dermatitis: Patients with atopic dermatitis have high levels of immunoglobulin E (IgE) and present with scaly, erythematosus, pruritic skin lesions, most commonly on the flexor surfaces.

Acne: More common in women than men, acne presents as papulo-pustular lesions on the face and other body areas. Rupture of these lesions releases free fatty acids, which further irritate the skin and extend the lesions. Both black open comedones and closed white comedones may be present.

Alopecia Areata: This autoimmune disease causes discrete, smooth, circular areas of hair loss on the scalp, without associated scaling, inflammation, or broken hair. It can involve a single or multiple areas.

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.

Common Skin Hypersensitivity Reactions and Their Causes

Toxic epidermal necrolysis is a severe skin hypersensitivity reaction that can be fatal and affects a large portion of the body’s surface area. It is often caused by drugs such as NSAIDs, steroids, and penicillins.

Morbilliform rash is a milder skin reaction that appears as a generalised rash that blanches with pressure. It is caused by drugs like penicillin, sulfa drugs, and phenytoin.

Erythema nodosum is an inflammatory condition that causes painful nodules on the lower extremities. It can be caused by streptococcal infections, sarcoidosis, tuberculosis, and inflammatory bowel disease.

Fixed drug reaction is a localised allergic reaction that occurs at the same site with repeated drug exposure. It is commonly caused by drugs like aspirin, NSAIDs, and tetracycline.

Erythema multiforme is characterised by target-like lesions on the palms and soles. It is caused by drugs like penicillins, phenytoin, and NSAIDs, as well as infections like mycoplasma and herpes simplex.

Understanding Common Skin Hypersensitivity Reactions and Their Causes

Differentiating Skin Lesions: Actinic Keratosis, Chondrodermatitis Nodularis Helicis, Basal Cell Carcinoma, Lentigo Maligna, and Seborrhoeic Keratosis

Skin lesions can be difficult to differentiate, but understanding their characteristics can aid in diagnosis and treatment. Actinic keratosis is a pre-malignant condition that is more common in sun-exposed patients, often presenting as scaly lesions on bald areas. Treatment with Efudix may initially worsen the lesions before improving. Chondrodermatitis nodularis helicis is a benign condition characterized by a tender, firm lesion on the ear due to pressure from sleeping on that side. It is treated with strong topical steroids and is not associated with a keratinous horn. Basal cell carcinoma is a common skin cancer associated with sun exposure, presenting with telangiectasia and a rolled edge. Lentigo maligna is a malignant lesion associated with sun exposure, typically pigmented and occurring on the face. Seborrhoeic keratosis is a common benign lesion that can mimic other lesions, but is not associated with sun exposure and is often found on the back, appearing stuck-on rather than scaly. Understanding the characteristics of these skin lesions can aid in accurate diagnosis and appropriate treatment.

Skin Conditions: Differential Diagnosis

Scabies Infection
A scabies infection is a likely diagnosis for a patient presenting with itching between the web spaces and in the groin. The infection is typically acquired through skin-to-skin contact, often after sexual intercourse. Symptoms may not appear until three to four weeks after initial contact, and treatment involves the use of a topical agent such as permethrin cream.

Atopic Dermatitis
Atopic dermatitis, or eczema, is an unlikely diagnosis for a patient presenting with symptoms in the groin and web spaces. It typically presents with a rash and itching on the flexor aspects of the joints and is unrelated to sexual activity.

Folliculitis
Folliculitis is an unlikely diagnosis for a patient presenting with symptoms in the groin and web spaces. It typically presents with pinpoint erythematosus lesions on the chest, face, scalp, or back and is unrelated to sexual activity.

Erythema Infectiosum Infection
Erythema infectiosum infection is a very unlikely diagnosis for a patient presenting with symptoms in the groin and web spaces. It primarily affects children and results from infection with parvovirus B19. Symptoms include a slapped cheek appearance, fever, headache, and coryza.

Keratosis Pilaris Infection
Keratosis pilaris is an unlikely diagnosis for a patient presenting with symptoms in the groin and web spaces. It typically affects the upper arms, buttocks, and thighs and presents with small white lesions that make the skin feel rough. It results from the buildup of keratin and is more common in patients with dry skin. It is unrelated to sexual activity.

Differential Diagnosis of Skin Conditions

Treatment Options for Scabies Infestation

Scabies infestation is a common condition that can affect anyone, but is more prevalent in individuals with poor personal hygiene, immunocompromisation, low socioeconomic status, and those working in industrial settings. The first-line treatment for scabies is the application of Permethrin 5% cream from the neck down for 8-14 hours, followed by washing it off. It is important to treat all household contacts simultaneously, even if they are symptom-free. Additionally, all affected linens should be washed and cleaned immediately.

While emollient cream can be applied regularly from the neck down, it will not treat the underlying infestation. Similarly, 5% Hydrocortisone cream applied twice daily to the hands will not address the underlying infestation. Oral antihistamines may provide relief from the symptomatic itch, but they do not treat the underlying infestation.

In cases where Permethrin is not effective, Malathion cream can be used as a second-line treatment for scabies. It should be applied from the neck down for 24 hours and then washed off. It is important to follow the instructions carefully and consult a healthcare professional if symptoms persist.

Next Steps in Psoriasis Treatment: Narrow-Band UVB Phototherapy

When topical treatments fail to improve psoriasis symptoms, the next step in treatment is often narrow-band ultraviolet B (UVB) phototherapy. While it has a reasonable success rate, it also comes with potential complications such as an increased risk of skin cancer. Patients with a history of skin cancer may not be recommended for this treatment.

Changing topical steroids would not be an appropriate step in the management plan. Instead, it is necessary to move onto the next step of the psoriasis treatment ladder. Biologics are not indicated at this stage and should only be considered as an end-stage treatment due to their high cost and significant side effects.

Psoralen with local ultraviolet A (UVA) irradiation may be appropriate for patients with palmoplantar pustulosis. However, for most patients, stopping steroids is not recommended. Instead, narrow-band UVB phototherapy should be commenced without stopping steroids to optimize treatment and increase the chances of success.

Common Skin Conditions: Asteatotic Eczema, Contact Dermatitis, Lichen Planus, Scabies, and Venous Ulceration

Asteatotic eczema is a skin condition that commonly affects elderly individuals due to over-washing and dry winter climate. It can also be associated with diuretic use and hypothyroidism. The condition causes dry, itchy skin with a unique crazy paving pattern on the limbs. Treatment involves using emollients and mild topical steroids.

Contact dermatitis, on the other hand, is caused by friction and environmental factors such as cold or exposure to chemicals like detergents and solvents. It typically affects the hands and does not display the crazy paving pattern seen in asteatotic eczema.

Lichen planus is characterized by a pruritic, papular eruption with a violaceous color and polygonal shape. It presents with a lace-like pattern, unlike the crazy paving pattern seen in asteatotic eczema.

Scabies is an itchy rash caused by mites that burrow under the skin’s surface. It often affects the very young and elderly, particularly those who live in crowded areas or institutional care. It presents with burrows, particularly on the web spaces between fingers, followed by a hypersensitivity rash. Treatment involves using topical insecticides like 5% permethrin.

Finally, venous ulceration is present on the lower limbs and can be itchy if associated with venous eczema. However, the legs often display a brown pigmentation of haemosiderin, and a venous ulcer would not present as described in this question.

In summary, understanding the characteristics of these common skin conditions can help with accurate diagnosis and appropriate treatment.

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

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 Rashes and Their Characteristics

Roseola infantum is a viral infection caused by herpesvirus 6. It is known to cause a rash that appears as small, pink, flat spots on the skin. The rash usually starts on the trunk and spreads to the limbs, neck, and face. Along with the rash, the infected person may also experience fever and swollen lymph nodes.

Erythema multiforme is a skin condition that causes red, raised, and blistering lesions on the skin. The lesions are usually circular or oval in shape and have a target-like appearance. They can appear on any part of the body, but are most commonly found on the hands, feet, and face. The condition is often triggered by an infection or medication.

Idiopathic thrombocytopenia is a blood disorder that causes a low platelet count. This can lead to easy bruising and bleeding, and in some cases, a petechial rash. Petechiae are small, red or purple spots on the skin that are caused by bleeding under the skin.

Henoch-Schönlein purpura is a condition that causes inflammation of the blood vessels. This can lead to a purpuric rash on the buttocks and lower limbs, as well as joint pain and abdominal pain. The condition is most commonly seen in children.

Meningococcal septicaemia is a serious bacterial infection that can cause a non-blanching purpuric rash. This means that the rash does not fade when pressure is applied to it. Other symptoms of the infection include fever, headache, and vomiting.

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.

Pityriasis Rosea

Pityriasis rosea (PR) is a common skin condition that typically affects adolescents and young adults. It is often associated with upper respiratory infections and is characterized by a herald patch, which is a circular or oval-shaped lesion that appears on the trunk, neck, or extremities. The herald patch is usually about 1-2 cm in diameter and has a central, salmon-colored area surrounded by a dark red border.

About one to two weeks after the herald patch appears, a generalized rash develops. This rash is symmetrical and consists of macules with a collarette scale that aligns with the skin’s cleavage lines. The rash can last for up to six weeks before resolving on its own.

Overall, PR is a benign condition that does not require treatment. However, if the rash is particularly itchy or uncomfortable, topical corticosteroids or antihistamines may be prescribed to alleviate symptoms. It is important to note that PR is not contagious and does not pose any serious health risks.

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.

Common Skin Disorders and Their Characteristics

Lichen planus is a skin disorder that has an unknown cause but is likely autoimmune. On the other hand, lichen sclerosus is characterized by itchy white spots that are commonly seen on the vulva of elderly women. Scabies, which typically affects children and young adults, causes widespread itching and linear burrows on finger sides, interdigital webs, and the flexor aspect of the wrist. Eczema usually presents as an itchy, red rash in the flexural areas, while psoriasis is characterized by itchy white or red patches on the extensor surfaces. These are some of the most common skin disorders and their distinct characteristics.

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.

Management of Hirsutism in Polycystic Ovary Syndrome: First-Line Options

Polycystic ovary syndrome (PCOS) is a condition characterized by irregular menstrual cycles, excess hair growth, and raised hormone levels. In patients with PCOS experiencing hirsutism and irregular periods, the first-line management option is the oral combined contraceptive pill. This medication reduces hyperandrogenism by suppressing ovarian androgen secretion and increasing binding of androgens, thereby reducing excess hair growth. Metformin can also be used to improve insulin resistance and aid weight management, but it would not be the first-line choice for managing hirsutism. Eflornithine can be used for hirsutism, but in this patient, starting the contraceptive pill will not only treat her hirsutism but also allow for regular withdrawal bleeds and regulate her menstrual cycle. The progesterone-only pill and topical minoxidil are not recommended as first-line options for managing hirsutism in PCOS patients.

Treatment Options for Localised Plaque Psoriasis

Localised plaque psoriasis is a chronic skin condition that causes red, scaly patches on the skin. There are several treatment options available, including Dovobet®, Infliximab, Methotrexate, Photochemotherapy (PUVA), and Retinoids.

Dovobet® is an ointment or gel that contains both calcipotriol and betamethasone dipropionate. It works synergistically to relieve the symptoms of localised plaque psoriasis. However, it is contraindicated for patients with certain conditions and precautions should be taken in prescribing for certain patients.

Infliximab is an anti-TNF alpha biologic agent that is used in systemic arthritis, particularly psoriatic arthritis. It is not used for localised plaque psoriasis.

Methotrexate is an antifolate immunosuppressant and chemotherapy agent. It would not be a first-line therapy for localised psoriasis.

Photochemotherapy (PUVA) is a type of ultraviolet radiation treatment that can be used for localised psoriasis but would not be first line.

Retinoids are derived from vitamin A and cause proliferation and reduced keratinisation of skin cells. They would not be first line for localised psoriasis.

In conclusion, the choice of treatment for localised plaque psoriasis depends on the severity of the condition, the patient’s medical history, and other factors. It is important to consult with a healthcare professional to determine the best course of treatment.

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.

Surgical Margins for Skin Cancer Excision

When removing skin cancer through excision biopsy, it is important to use appropriate surgical margins to ensure complete removal of the cancerous cells. The size of the margin depends on the type and thickness of the cancer.

For melanomas, a 2 mm margin is used for the initial excision biopsy. After calculating the Breslow thickness, an additional wide excision is made with margins ranging from 1 cm to 2 cm, depending on the thickness of the melanoma. A 1 cm margin is used for melanomas measuring 1.0–4.0 mm, while a 2 cm margin is used for melanomas measuring >4 mm.

Squamous-cell carcinoma (SCC) requires a 4 mm excision margin, while basal-cell carcinoma (BCC) requires a 3 mm margin.

Using appropriate surgical margins is crucial for successful removal of skin cancer and preventing recurrence.