Definition:

Bullous pemphigoid is the predominant type of autoimmune blistering disease that affects the subepidermal layer

Bullous pemphigoid often manifests in those aged 80 and above, mainly affecting those aged 50 and above. Although bullous pemphigoid in newborns and children is rare, it can happen in younger individuals.

Etiology:

Bullous pemphigoid occurs when IgG and IgE immunoglobulins (antibodies) and activated T lymphocytes (white blood cells) attack the basement membrane of the epidermis. The target protein is BP180, also known as Type XVII collagen, or occasionally BP230, which is a plakin. The proteins are located inside the NC16A domain of collagen XVII. They are linked to the hemidesmosomes, which are structures responsible for the adhesion of epidermal keratinocyte cells to the dermis, creating a water-resistant barrier.

The autoantibodies attaching to the proteins and subsequent release of cytokines from the T cells result in complement activation, recruitment of neutrophils (acute inflammatory cells), and the release of proteolytic enzymes. These disrupt the hemidesmosomes and induce the development of blisters under the epidermis.

Clinical features:

Bullous pemphigoid causes intense pruritus and typically results in the development of large, tense fluid-filled vesicles/bullae (blisters) arising on urticarial background that eventually rupture leading to the formation of crusted erosions.

Bullous pemphigoid commonly affects the flexor surfaces of the limbs. It might be confined to a specific location or extend over the trunk.

• It frequently affects the skin in areas where there are folds or creases.
• Occurrence of blisters within the oral cavity and the genital area areas is infrequent.

Some individuals are diagnosed with bullous pemphigoid even if they do not have any bullae, which is known as non-bullous pemphigoid. This may affect any part of the body.

Diagnosis:

The diagnosis is suspected clinically when typical bullae are present. A skin biopsy of an early lesion will typically confirm  the diagnosis. The diagnosis can also be made from inflamed, non-blistered epidermis.

The pathological examination of bullous pemphigoid reveals a separation beneath the epidermis. A dermal neutrophilic infiltrate is commonly observed, although it may not be present in all cases. Eosinophils may be prominent.

Direct immunofluorescence staining of a skin sample collected next to a blister reveals antibodies specifically located along the basement membrane, which is situated between the epidermis and dermis.

Management:

Pharmacologic therapy for bullous pemphigoid primarily relies on immunosuppressants and other anti-inflammatory medications. Patients may need treatment for up to several years

Most of the morbidity and mortality associated with bullous pemphigoid results from the association between patient comorbidities and treatment side effects rather than from the disease itself. Thus, it is advisable to adopt a cautious approach to treatment, using only the necessary amount of medication to achieve remission.

The primary mode of therapy for bullous pemphigoid typically includes one of the following as the initial treatment:

• High potent topical corticosteroid (such as clobetasol propionate)
• Oral Corticosteroid (such as prednisone or prednisolone)
• Doxycycline

Corticosteroid-sparing agents (e.g., doxycycline, dapsone, methotrexate, mycophenolate, azathioprine) are frequently added to an oral corticosteroid regimen after achievement of disease control in an attempt to facilitate corticosteroid tapering. This is because bullous pemphigoid is a chronic condition and because systemic corticosteroids have multiple toxic side effects.

Written by:

Mashael Alanazi, Medical Intern.

Revised by:

Naif Alshehri, Medical Intern.

Resources:

DermNet

Review of Dermatology textbook

Definition: 

Pemphigus vulgaris is a rare autoimmune disorder characterized by painful blisters and erosions on the skin and mucous membranes, typically seen in the oral cavity. Pemphigus vulgaris is responsible for 70% of all cases of pemphigus globally.

Epidemiology:

Pemphigus vulgaris can occur in individuals of any race, age, or gender. The condition often manifests itself in individuals aged 30 to 60 and is more prevalent among individuals of Jewish and Indian descent compared to other ethnic groups, perhaps due to hereditary factors.

Drug-induced pemphigus is a recognized condition that is mostly caused by penicillamine, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and cephalosporins.

Etiology:

Pemphigus vulgaris is a blistering autoimmune disease. 

Keratinocytes are adhered together at distinct adhesive sites known as desmosomes. Pemphigus vulgaris is a condition where autoantibodies of the immunoglobulin type G (IgG) attach to a protein called desmoglein 3 (dsg3). This protein is located in the desmosomes of the keratinocytes, which are in the lower part of the epidermis. The outcome is the keratinocytes undergo separation, leading to their replacement by fluid, resulting in the formation of a blister. Approximately half of the individuals diagnosed with pemphigus vulgaris have anti-dsg1 antibodies.

Clinical features:

The majority of individuals with pemphigus vulgaris initially exhibit lesions on the mucous membranes, specifically in areas such as the mouth and genitals. Blisters often form on the skin within a few weeks or months, however in certain cases, only mucosal lesions may be present as a manifestation of the disease. 

Skin lesions manifest as thin-walled flaccid blisters containing transparent fluid that easily rupture resulting in itchy and painful erosions. They primarily occur on the upper chest, back, scalp, and face. Erosions occurring in the skin folds have the potential to progress into vegetative lesions characterized by a granular and crusty appearance, a condition known as pemphigus vegetans.

Characteristics of oral mucosal pemphigus include:

• Oral lesions are seen in 50-70% of individuals.
• Shallow blistering and erosion.
• Widespread engagement inside the oral cavity.
• Painful, slow-healing ulcers.
• Difficulty eating and drinking.
• Spread to the larynx, resulting in hoarseness when talking.

Diagnosis:

A biopsy of a blister is typically necessary to diagnose pemphigus vulgaris. The histological examination usually reveals keratinocytes that are rounded and separated (acantholytic cells) located immediately above the basal layer of the epidermis.

Pemphigus is confirmed by the use of direct immunofluorescence staining on skin biopsy sections taken from areas surrounding the lesions. This staining process helps to identify the presence of immunoglobulin (Ig)G antibodies or complement on the surfaces of keratinocytes.

Treatment: 

The main objective of treating pemphigus vulgaris is to reduce the occurrence of blisters, prevent infections, and facilitate the healing process of blisters and erosions. Systemic corticosteroids are the primary method of medical treatment for managing the condition. Typically, this involves administering moderate to high dosages of oral prednisone or prednisolone or using pulsed intravenous methylprednisolone. Corticosteroids do not provide a cure for the disease, but they enhance the patient’s quality of life by decreasing disease activity. Administering the necessary dosages of corticosteroids to manage pemphigus vulgaris and the duration of treatment might lead to significant adverse effects and potential hazards.

The duration of therapy and the corticosteroid dosages required to manage pemphigus vulgaris can have major risks and adverse effects.

Patients with pemphigus vulgaris may require other immunosuppressive drugs for years in order to lower the dosage of steroids. These are typically:

• Azathioprine
• Mycophenolate mofetil
• Cyclophosphamide
• Rituximab. 

Topical therapy— refers to the use of medications or treatments that are applied directly to the skin or mucous membranes to treat a specific condition or disease.

Topical treatment for cutaneous pemphigus vulgaris may involve the use of topical corticosteroids and moisturizers.

The management of mucosal pemphigus vulgaris may involve the use of different preparations of a topical corticosteroid, intralesional corticosteroid, topical tacrolimus, or topical ciclosporin.

General management:

Proper wound care is crucial, as it helps facilitate the healing process of blisters and erosions.

• When changing dressings, it is important to wear surgical gloves and follow the aseptic method.
• Analgesics may be necessary, particularly when changing dressings.
• Drain blisters that are still intact, but maintain the blister roof.
• Apply non-adherent dressings (silicone mesh or gauze soaked in petrolatum, for example). 
• Patients should limit activities that may damage the skin and mucous membranes while the condition is active. These activities include contact sports and eating food that has the potential to irritate or injure the oral cavity, such as spicy, acidic, hard, and crunchy meals.

Maintaining oral hygiene and practicing adequate dental care are crucial.

Written by:

Mashael Alanazi, Medical student 

Revised by:

Naif Alshehri, Medical Intern

Resource:

DermNet

Necrolytic acral erythema is a skin disease that appears in the toes and the feet. It was first described in the literature in 1996. It is known as the cutaneous marker for hepatitis C infection and is strongly linked with it. The majority of recorded cases, which have an equal sex frequency and a mean onset age of 40–45 years (range 11–78 years), have been in people with skin of color, including Asians and Africans.

Causes: 

Necrolytic acral erythema is thought to be multifactorial, possibly due to low blood levels of albumin, glucagon, and amino acids caused by liver failure, dietary deficiencies (particularly zinc insufficiency), and hereditary factors.

The most common cause is hepatitis C infection, where a study conducted in the USA suggested that necrolytic acral erythema was observed in 1-2% of patients with chronic hepatitis C. The second most common association was found to be zinc deficiency occurring with various other disorders including coeliac disease and Crohn’s disease. It is important to note that for the hepatitis C virus to replicate, zinc is a necessary cofactor. 

Interestingly, the prevalence of chronic hepatitis C infection is high in Japan, in contrast, there are no reported cases of necrolytic acral erythema. This could be a result of genetic predisposition or the prevalent hepatitis C genotypes in that group.

Clinical features:

Usually, the tops of the toes and feet are affected by necrotic acral erythema. The skin lesions are painful most of the time, although they might also occasionally be itchy or burning. 

Acute cases present as erythematous lesions with a margin of erosions or flaccid bullae. 

Chronic cases can be divided into three phases:

• The initial phase presents with ducky scaly papules or plaques. 
• The well-developed phase presents with large hyperpigmented well-demarcated papules and plaques. 
• The late phase presents with thin psoriasiform hyperpigmented lesion with a well-defined dark red rim.

Dermoscopy shows the following findings:

• Central white and brown peripheral globules. 
• Irregular red spot in the center. 
• Brown background.
• Dull white scale.

Diagnosis:

• Laboratory investigations include hepatitis C serology, liver function tests, and serum zinc.
•  A skin biopsy is used to confirm the diagnosis and it shows inflammatory infiltrate, hyperkeratosis, parakeratosis, epidermal spongiosis, and focal necrosis. 

Differential diagnosis:

Necrolytic migratory erythema is one of the most important differential diagnoses, as it has similar skin biopsy results. Other differentials include psoriasis, pellagra, and biotin-responsive dermatoses. 

Management:

Treat the underlying causes mostly hepatitis C with combination therapy with interferon and ribavirin, and oral zinc supplements (220 mg BID) which could enhance the effects of hepatitis C treatment. 

Complications:

Complications of hepatitis C due to missing the diagnosis. Other complications include lichenification and fissuring. 

Prognosis:

The disease follows a relapsing-remission course, with appropriate treatment it can resolve, however, recurrence could be observed if treatment is stopped. 

Written by:

Mohammed Alahmadi, Medical Student. 

Revised by:

Maee Barakeh, Medical Student. 

References:

DermNet

Medscape

Andrews’ Diseases of The Skin, Clinical Dermatology 

Dermatology by Bolognia

Langerhans cell histiocytosis (LCH) is a rare multisystem disorder. It is a reactive increase in the number of Langerhans cells which act as antigen-presenting cells in the epidermis. It most commonly affects children from 1 – 3 years of age. It is slightly more common in males. LCH affects 2–5 children per million per year with an estimated prevalence of 1:50 000 children under 15 years of age. LCH has been associated with Epstein-Barr virus in some cases.

Classification:

This condition can appear in a variety of forms, and several of the well-known patterns have been given unique names. These include:

• Letterer-Siwe disease: Usually in children less than two years of age, involves many organs including bones, lungs, and the liver. Skin affection can appear in the scalp, trunk, and groin manifesting as pinkish papules or blisters that me crust. It can mimic cradle cap which is seen in seborrheic dermatitis.
• Hand-Schuller-Christian disease: Usually in children from 2 – 6 years of age, the skin and bone especially the skull. Manifest as a pinkish-crusted papule, with ulcers in the mouth or genitals, and rarely eye protrusion. It often results in diabetes insipidus.
• Eosinophilic granuloma: Usually in school-age children, less commonly affects the skin, usually present as a single bone lesion.
• Congenital self-healing reticulohistiocytosis: Usually present at birth as a widespread reddish lump on the skin which breaks and results in a crust that fades with time with no intervention. It is limited to the skin.

A newer classification is also used where it is based on the number of involved organs in a single system (SS-LCH) and multisystem (MS-LCH) disease.

Diagnosis:

The diagnosis is suspected with the described rash and X-ray scans of internal organs. LCH is confirmed by skin biopsy. When histiocytosis is diagnosed in one organ, other organs should be checked to detect if it was affected.

Management:

If the disease was limited to the skin the following therapies could be utilized: topical corticosteroids, topical antibiotics, photochemotherapy, and thalidomide. In cases of pain lesions, the following medications can be used non-steroidal anti-inflammatory drugs, steroids injection, and radiotherapy.

In cases of multisystem involvement, starting with oral corticosteroids, then chemotherapy is warranted. The choice of treatment depends on several factors including age, and organ involvement. BRAF-V600 inhibitors may be beneficial such as vemurafenib and dabrafenib.

Prognosis:

Many people may have little or no symptoms of a minor disease that is limited to one organ. There is an excellent prognosis for these individuals. In cases of several organ involvement, it could be fatal. In those younger than two years, a disease involving multiple organs, and vital organs such as the liver are the predictor of poor outcomes in LCH. The mortality rate for children under two years old who have multiple organ involvement from LCH is between 40-50%.

Written by:

Mohammed Alahmadi, Medical Student.

Revised by:

Maee Barakeh, Medical Student.

References:

DermNet

Dermatology by Bolognia

Practical Guide to Dermatology, The Henry Ford Manual

Primary Care Dermatology Society

What is Flegel disease?

Flegel disease is often referred to as hyperkeratosis lenticularis perstans. Flegel described for the first time in 1958. It is distinguished by red-brown papules with irregular, horny scales found primarily on the top surface of the feet and lower legs.

Causes of Flegel disease 

The exact cause of the condition is uncertain. It is assumed to be a hereditary disorder.

It is assumed to be an inherited disorder, although the disease has been found in people with no family history. Sun exposure has also been linked, but not proven.

Clinical features of Flegel disease

Lesions are tiny, red-brown, scaly papules ranging in size from 1 to 5 mm that typically cover the surface of the foot and lower legs. When the scale is removed, a bright red base appears, typically with pinpoint bleeding. In rare cases, the outer ear lobes, arms, palms, soles, and oral mucosa may be impacted. The papules are usually painless.

Diagnosis of Flegel disease

Flegel disease is sometimes clinically diagnosed, particularly if there is a family history of the condition. Otherwise, a biopsy could reveal a pathological diagnosis of Flegel disease.

Treatment for Flegel disease

Lesions are benign and are primarily treated for cosmetic reasons. Treatment for Flegel illness includes:

– 5% fluorouracil cream was used topically for several months.
– Dermabrasion
– Cryotherapy
– Topical Retinoids
– Oral retinoid like isotretinoin or acitretin

Written by:

Atheer Alhuthaili , medical student.

References:

DermNet

What is tinea corporis?
Tinea corporis is a superficial fungal infection of the skin that affects any region of the body, excluding the hands and feet, scalp, face and beard, groin, and nails. It is often known as ‘ringworm’ because of its distinctive ring-shaped lesions.

Risk factors for tinea corporis

• Previous or concomitant tinea infections
• Diabetes mellitus
• Immunodeficiency
• Hyperhidrosis
• Xerosis
• Ichthyosis
• Hot, humid climates
• Household crowding
• Keeping house pets
• Recreational activities that include close contact with people.

Causes of tinea corporis

Tinea corporis is mostly caused by dermatophyte fungi of the genera Trichophyton and Microsporum .The most prevalent cause of tinea corporis is T. rubrum. It can also be caused by T. interdigitale, T. tonsurans, M. canis, T. verrucosum, T. equinum, and T. erinacei species. Infection can be acquired through direct skin contact with an infected person or animal, contact with fomites, or secondary dissemination from other sites of dermatophyte infection.

Clinical features of tinea corporis

Tinea corporis first appears as a single circular red patch with a raised, scaly leading edge. A lesion spreads from the center to form a ring with central hypopigmentation and a scaly red rim (ringworm). The border may be papular or pustular. Itching is common. Multiple lesions can develop over time, which may lead to the formation of a polycyclic pattern. The distribution of lesions is often asymmetric.

Diagnosis of tinea corporis

Tinea corporis is usually diagnosed clinically after taking a complete history and physical examination. However, tests can be performed to confirm the diagnosis. Skin scrapings are examined under a microscope with KOH preparation, which will show branching, segmented hyphae. A fungal culture is another method to confirm the diagnosis. Tinea corporis is sometimes diagnosed with a skin biopsy.

Treatment for tinea corporis

General Measures:

The skin should be kept clean and completely dried. In hot and humid areas, loose-fitting, light clothes are recommended. Avoid close contact with infected people and the sharing of fomites.

Specific measures:

Topical antifungal treatments like imidazoles and terbinafine. It’s used to treat localized tinea corporis.

Oral antifungal treatment is often needed if tinea corporis affects a hair-bearing site, is widespread, or has not responded to topical antifungals. Terbinafine and itraconazole are the recommended oral antifungal medications.

Written by:

Atheer Alhuthaili , medical student.

Revised by:

Maee Barakeh , medical student.

References:

DermNet.

UpToDate.

Medscape.

Amboss.