What is Seborrheic dermatitis?

Seborrheic dermatitis (SD) is a chronic inflammatory skin condition characterized by erythematous, scaly patches primarily in seborrheic areas—regions rich in sebaceous glands such as the scalp, face, and upper trunk. There are infantile and adult forms of seborrhoeic dermatitis.

 Who gets Seborrheic dermatitis?

Seborrhoeic dermatitis affects 3% to 12% of the population and has two main age distributions:   

Infants: Under 3 months old; usually resolves by 6-12 months.

Adults: It typically begins in late adolescence, is more common in males, and tends to peak during young adulthood and later in life. Various factors are linked to more severe cases in adults, including having oily skin, a family history of seborrhoeic dermatitis or psoriasis, and conditions causing immunosuppression, such as organ transplants, HIV, or lymphoma. Additionally, neurological and psychiatric disorders like Parkinson’s disease, depression, and epilepsy, as well as the use of neuroleptic medications, can contribute to its severity. Other contributing factors include PUVA therapy for psoriasis, lack of sleep, and stressful life events.

Causes of seborrhoeic dermatitis

The exact cause of seborrhoeic dermatitis is not fully understood. However, various factors are thought to be associated with the condition, including hormonal changes, fungal infections, nutritional deficiencies, and neurogenic factors. The proliferation of Malassezia yeast is believed to contribute to its development. Malassezia, a normal skin saprophyte, produces lipases and phospholipases that break down triglycerides in sebum into free fatty acids, which may trigger inflammation. Differences in skin barrier lipid composition and function may account for the varying manifestations of the condition. 

Clinical features of Seborrhoeic dermatitis

Infantile seborrhoeic dermatitis

Seborrhoeic dermatitis in infants, also known as cradle cap, features:

• Diffuse, greasy, yellow scaling on the scalp.
• The rash may extend to the armpit and groin folds.
• Salmon-pink patches that may flake or peel.
• Generally not itchy

Adult seborrhoeic dermatitis

Seborrheic dermatitis typically follows a chronic course characterized by episodic phases. Active phases may include symptoms such as burning and itching, while these are interspersed with inactive, asymptomatic periods. The condition usually flares in winter and improves with sun exposure in the summer. It manifests with a range of symptoms, from erythematous plaques with patchy scaling to greasy yellow crusts, and is commonly distributed in areas with hair and oily skin. The affected regions include:

• Scalp (dandruff and itching)
• Forehead/hairline and retro auricular area
• Nasolabial fold, eyebrows, and periocular region (blepharitis with scaly, red eyelid margins)
• Cheeks and chin
• Presternal and interscapular regions
• Axillae, under the breasts, umbilicus, and groin area

People with darker skin may show scaly, hypopigmented macules and patches in affected areas.

Diagnosis of Seborrhoeic dermatitis

Seborrhoeic dermatitis is usually diagnosed clinically based on lesion location, appearance, and behavior. If uncertain, a biopsy may be performed. Histological findings in seborrhoeic dermatitis typically include:

• Parakeratosis in the epidermis
• Plugged follicular ostia
• Spongiosis (intercellular edema in the epidermis)
• A sparse, perivascular, lymphohistiocytic inflammatory infiltrate in the dermis

Treatment of Seborrhoeic dermatitis

General Measures

1. Patient Education:
   • Explain the nature of the condition and appropriate skincare routines.
2. Lifestyle Modifications:
   • Diet: A high fruit intake may reduce symptoms.
   • Stress Management: Stress can trigger flare-ups, so managing stress is important.
3. Many herbal remedies are used, but their effectiveness is unclear.

Specific Measures

1. Keratolytics:
   • Salicylic Acid, Lactic Acid, Urea, Propylene Glycol: Used to remove scales.
2. Topical Antifungal Agents:
   • Ketoconazole, Ciclopirox: Reduce Malassezia.
   • If resistant: Zinc Pyrithione or Selenium Sulfide.
3. Mild Topical Corticosteroids:
   • Use for 1–3 weeks to reduce inflammation during acute flare-ups.
4. Topical Calcineurin Inhibitors:
   • Pimecrolimus Cream, and Tacrolimus Ointment: Alternatives for long-term use, especially on the face.
5. Resistant Cases in Adult :
   • Oral Itraconazole, tetracycline antibiotics, or phototherapy.
   • Low-Dose Oral Isotretinoin: Effective for severe cases.
6. Roflumilast 0.3% Foam: Recently FDA-approved for use in patients aged 9 years and older.

Written by:

Atheer Alhuthaili, Medical Intern.

Revised by:

Naif Alshehri, Medical Intern.

References:

DermNet.

Amboss

Definition:

Atopic dermatitis, also known as atopic eczema, is the most prevalent inflammatory skin condition that is observed globally. It manifests as widespread dryness, itching, and a rash.

Epidemiology:

Approximately 230 million individuals worldwide suffer from atopic dermatitis, with a lifetime prevalence exceeding 15%, particularly in more affluent cultures. It usually impacts individuals who have a tendency for atopic conditions, which often tend to coincide with hay fever, asthma, and food allergies.

Typically, atopic dermatitis begins during infancy and can impact up to 20% of children. Around 80% of children who are affected experience the disease before they reach the age of 6. People of all age groups can be affected. 5–15% of young adults up to the age of 26 have it, despite the fact that it can settle in late childhood and adolescence.

Etiology:

Atopic dermatitis arises from a complex interaction of environmental and genetic aspects. 

Atopic dermatitis (eczema) is a complex condition with multiple factors contributing to its development, making it difficult to identify a single cause. There are numerous theories concerning the underlying mechanisms. Ongoing research is exploring various factors, including the immune system, mutations in skin structural genes, abnormalities in skin cells (keratinocytes), and the presence of bacteria, viruses, and yeasts on the skin surface.

Clinical features:

The hallmark symptoms of AD at every stage include dry skin and pruritus. Subacute and chronic AD is characterized by dry, scaly, or excoriated papules or skin thickening (lichenification) from persistent scratching, but acute AD is characterized by erythematous papules and vesicles with exudation and crusting. 

Clinical course and complications: AD progresses over months to years in a chronic, relapsing manner. Individuals who have mild disease may go through periods of intermittent flares followed by spontaneous remission. However, those with moderate to severe dermatitis typically do not experience complete clearance without receiving treatment.

Diagnosis:

The diagnosis of AD is clinical, which is established by evaluating the history, morphology, location of skin lesions, and related clinical symptoms. The diagnostic criteria include: 

• Pruritus 
• Eczematous dermatitis (acute, subacute, chronic) with characteristic morphology and age-specific patterns:

Facial, neck, and extensor involvement in neonates and young children

Flexural lesions in any age group, either present or past

Sparing the groin and axillary regions.

• History of chronic or relapsing conditions

Management:

The primary objectives of managing atopic dermatitis (AD) are to alleviate symptoms (pruritus and dermatitis), avoid worsening of the condition, and minimize the potential risks associated with therapy. 

Management includes the removal of aggravating factors, restoration of the skin barrier function and moisturization of the skin, patient education, and pharmacological intervention for skin inflammation. 

• Patient education is a crucial element of effective management. Patients are advised to: 

– Regularly apply emollients to maintain skin hydration. 

– Minimize aggravating elements such as: excessive bathing/washing without then moisturizing, exposure to cold, low-humidity conditions, excessive heat and perspiration, exposure to solvents, and strong detergents.

• Patient with mild to moderate atopic dermatitis: 

Topical therapies: Patients presenting with mild to moderate symptoms are treated with topical treatments.

The recommendation for the majority of patients with mild to moderate AD is to use topical corticosteroids and emollients instead of other topical anti-inflammatory medications. 

Topical calcineurin inhibitors like pimecrolimus and tacrolimus are topical immunomodulators and work in a different way from corticosteroids, they are suitable for treating atopic dermatitis in sensitive sites such as the eyelids, skin folds, and genital area. It can be used interchangeably with topical corticosteroids.  

• Patients with moderate to severe atopic dermatitis:

Patients with chronic, moderate to severe disease that does not improve with the best available topical therapy need a systemic treatment. For the majority of these patients, administration of a biologic immunomodulatory agent (dupilumab, tralokinumab, or lebrikizumab) instead of traditional immunosuppressants, other immunomodulators, or phototherapy is recommended 

Written by:

Mashael Alanazi, Medical Intern

Revised by:

Naif Alshehri, Medical Intern

Resources:

DermNet

UpToDate

Definition and epidemiology:

Neurofibromatosis type 1, also called Von Recklinghausen’s disease, is a genetic disorder characterised by cutaneous as well as peripheral and/or central nervous system neoplasms. Neurofibromatosis type 1 incidence rate is approximately 1 in 3000 births.

Pathogenesis:

Neurofibromatosis type 1 is inherited in an autosomal dominant pattern. 50% of patients have de novo mutations that occur in paternally derived chromosomes. 

NF1 is caused by pathogenic variants of NF1 gene, located in chromosome 17q11.2. The gene encompasses a protein called neurofibromin.

Clinical features: 

The clinical features of NF1 are myriad and vary in frequency.

Café-au-lait macules– are flat, uniformly hyperpigmented macules that appear during the first year after birth and usually increase in number during early childhood . The number of café-au-lait macules then stabilizes over time. Up to 15 percent of the general population has one to three café-au-lait macules; however, the presence of six or more café-au-lait macules is highly suggestive of NF1. Approximately 95 percent of adults with NF1 have café-au-lait macules, but they tend to fade later in life and may be difficult to distinguish in older individuals.

Freckling– Freckling in the axillary or inguinal regions (Crowe sign) is a diagnostic criterion distinct from café-au-lait macules. Freckling usually is not apparent at birth but often appears by age three to five years, typically first in the inguinal region.

Lisch nodules – Lisch nodules are raised, tan-coloured hamartomas of the iris and represent a specific finding for NF1. 

Neurofibromas – Neurofibromas are the most common type of benign tumour that develops in people with NF1. Neurofibromas are benign peripheral nerve sheath tumours that are composed of a mixture of Schwann cells, fibroblasts, perineurial cells, mast cells, macrophages, and T cells.

• Cutaneous neurofibromas: are  skin-coloured  to  pink,  tan,  or  brown  papulonodules  that  are  soft  or slightly  rubbery  in  texture  and  can  range  from  a  few  millimetres  to several  centimetres  in  diameter.  While  fully  formed  CNFs  are  often dome-shaped  or  pedunculated,  early  lesions  may  be  barely  elevated. They  invaginate  easily  with  gentle  pressure,  exhibiting  the  pathogno- monic “buttonhole” sign.
• Subcutaneous neurofibromas occur deeper in the dermis and subcutis, tending to be firmer and less well-circumscribed than cutaneous neurofibromas.
• Plexiform neurofibromas may track along nerves to create tender, firm nodules or masses in the subcutaneous tissue with a  “bag  of  worms”  consistency  upon  palpation.

Neurological manifestations – these include optic gliomas, learning difficulties, speech problems and behavioural issues.

Skeletal manifestations – Macrocephaly,  hypertelorism,  scoliosis, and  osteopenia  are common  cranioskeletal  abnormalities  in  individuals  with  NF1.  A highly distinctive but less common finding is pseudarthrosis of the long bones, most often the tibia. Sphenoid wing dysplasia is a congenital, typically unilateral bony defect in the posterior wall of the orbit.

Cardiovascular manifestations – Hypertension is a common finding in NF1 patients. Although essential hypertension  is  most  frequent,  renovascular  stenosis  (especially  in children)  and  unsuspected  pheochromocytomas may  be  the  cause in  some  patients. Pulmonary stenosis can occur in 1% of NF1 patients.

Diagnosis:

The diagnosis of NF1 is based upon the presence of characteristic clinical features. Genetic testing is not required to make the diagnosis but can be helpful in establishing the diagnosis in children who do not meet diagnostic criteria.

Diagnostic criteria – Two or more of the following must be present:

• Six or more café-au-lait macules >5 mm in prepubertal individuals and >15 mm in postpubertal individuals. 
• Two or more neurofibromas of any type or one plexiform neurofibroma.
• “Freckling” in the axillary or inguinal regions.
• Optic gliomas.
• Two or more Lisch nodules (iris hamartomas).
• Osseous lesions, such as sphenoid wing dysplasia or thinning of long bone cortex, with or without pseudarthrosis .
• First-degree relative (parent, sibling or offspring) with NF1 by the above criteria.

Management: 

Management of patients with NF1 requires a multi-disciplinary approach. Dermatologists  are  often  consulted  to  assist  in  establishing  the diagnosis in  affected  children. Goals  of  longitudinal  care  include  early  recognition  and  treatment  of complications, maximization of academic and vocational achievement, and minimization of the disease’s psychosocial impact. 

Plexiform neurofibromas (PNF)  may  grow  into  large,  bulky  tumors  during early  childhood.  Multidisciplinary  teams  are  often  required  to  excise deep  and  extensive  neurofibromatous  tissue,  and  the  lesions  tend  to recur  following  surgery.

Café-au-lait macules do  not  need  or  respond  well  to  treatment,  although  it  may  be  desired  for  cosmetic  purposes.  When  laser therapy  is performed,  CALMs  tend  to  persist  or  recur.

Lifelong  surveillance  for  the  development  of  Malignant peripheral nerve sheath tumors (MPNST)  is  essential, particularly for patients at increased risk of this malignancy due to the known presence of PNFs, polyneuropathy secondary to multiple nerve root  tumors,  a  history  of  radiation  therapy,  or  a  germline  NF1  microdeletion. PET- CT scan can aid in the early detection of malignant change within Plexiform neurofibromas.

Written by:

Bandar Alharbi, Medical Intern

Revised by:

Naif Alshehri, Medical Intern

Resources: 

Dermnet

UpToDate

Bolognia Dermatology textbook

What is Ataxia-telangiectasia?

Ataxia-telangiectasia, also known as Louis-Bar syndrome, is a rare inherited multisystem disorder distinguished by: ataxia, oculocutaneous telangiectasia, immunodeficiency, and cancer susceptibility, as well as radiation toxicity.

Causes of Ataxia-telangiectasia

Ataxia-telangiectasia is an autosomal recessive disorder in which one ataxia-telangiectasia gene is inherited from each parent. ATM gene inactivation mutations are found on chromosome 11q22-23. In Purkinje cells of the cerebellum, as well as in brain, skin, and conjunctival endothelial cells, the ATM gene codes a protein kinase that is important for double-strand-break DNA repair.

Clinical features of Ataxia-telangiectasia

Children with ataxia-telangiectasia appear normal at birth, and symptoms do not show until they learn to walk at age one or two.

Neurological manifestations:

• Unsteady walk
• Abnormal jerky movements
• Poor coordination of the limb
• Slow and slurred speech
• Facial features: dull, sad, inattentive
• Growth is delayed
• One-third of patients experience learning difficulties

Oculocutaneous manifestations:

Telangiectases are the second most common clinical manifestation of ataxia-telangiectasia. Dilated conjunctivae vessels appeared first at the angles of both eyes and spread horizontally in the equatorial region of the conjunctivae toward the corneal limb. They may have a subtle effect on the internal ears, eyelids, and cubital and popliteal fossas. Telangiectasia patches in other areas of the skin are less common. 

Some gray hairs are usually noticed, even in young children. During adolescence, the facial skin becomes atrophic and sclerodermoid, with atrophic areas resembling large varicella scars. Pigmentary changes occur in a mottled pattern of hypopigmentation and hyperpigmentation.

Additional skin changes may include:

• Café au lait spots
• Vitiligo
• Cutaneous granulomas: red-brown nodules and infiltrating ulcerative plaques are frequently seen on the face and limbs.
• Seborrheic dermatitis, keratosis pilaris, common warts, and hirsutism of the arms and the legs are also frequently found. 
• Multiple senile keratoses and basal cell carcinomas of the face have been reported in patients in their 20s.                                                                                                                                                                                                                                          

Patients with ataxia-telangiectasia have a compromised immune system, making them susceptible to recurring sinus and bronchial infections. Also, they are at a greater risk of developing malignancies.

Diagnosis of Ataxia-telangiectasia

The clinical suspicion of ataxia telangiectasia is supported by:

• Elevated serum levels of alpha-fetoprotein (AFP)
• A cytogenetic study may help confirm the diagnosis (7;14 translocations).
• The molecular diagnosis.

If a parent has an inactivating ATM gene mutation, a prenatal diagnosis can be made. 

Treatment of Ataxia-telangiectasia

There is no cure for ataxia-telangiectasia. The management of ataxia-telangiectasia focuses on treating symptoms, preventing complications, and, most importantly, supporting patients and their families. This could involve physiotherapy, speech therapy, and antibiotics for infection. Death usually occurs in early or middle adolescence, mainly from bronchopulmonary infection, less frequently from cancer, or a combination of both.

Written by:

Atheer Alhuthaili , Medical Student.

Revised by: 

Naif Alshehri, Medical Intern.

Article References:

DermNet.

Uptodate.

Amboss

Picture Reference:

Bolognia 4th edition.

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