Definition:

Erythema multiforme is an immune-mediated illness that usually resolves on its own. It affects the skin and mucous membranes, and is characterized by the presence of “target” lesions. Erythema multiforme major can be distinguished from multiforme minor by the presence of significant mucosal involvement. Episodes can manifest as either solitary, recurrent, or persistent.

Etiology:

1-Approximately 90% of cases are triggered by infection, with HSV type 1 being the predominant cause. Additional infectious triggers include:

• HSV type 2
• Cytomegalovirus
• Epstein-Barr virus
• Influenza virus
• Vulvovaginal candidiasis
• SARS-CoV-2
• Orf.

2-Medications that can potentially cause erythema multiforme include:

• Antibiotics (including erythromycin, nitrofurantoin, penicillins, sulfonamides, and tetracyclines)
• Anti-epileptics
• Non-steroidal anti-inflammatory drugs
• Vaccinations (most common cause in infants).

3-Additional disorders that are commonly linked to erythema multiforme, particularly in cases of chronic disease, include:

• Inflammatory bowel disease
• Hepatitis C
• Leukaemia
• Lymphoma
• Solid organ cancer malignancy

Clinical features:

Cutaneous features:

• Cutaneous lesions initially appear on the periphery and then move centrally.
• The distribution is typically symmetrical, with a tendency to favor extensor surfaces.
• May cause pain, itching, or swelling.
• Initial lesions manifest as circular, red papules that subsequently progress into target-shaped lesions.

Target lesions are characterized by three concentric rings of color variation:

-A dark, central region of epidermal necrosis

-Encircled by a less swollen area

-Surrounded by an erythematous periphery.

Atypical lesions can coexist alongside typical lesions. Atypical lesions exhibit elevated surfaces with indistinct boundaries.

In severe disease, up to hundreds of lesions in varying developmental stages may be present making it challenging to distinguish characteristic lesions.

Mucosal features:

• Lesions form as blisters, which then rupture to reveal superficial erosions covered by a white pseudo-membrane.
• Erythema multiforme primarily affects the oral membranes, but can also manifest with urogenital and, infrequently, ocular lesions.
• When the mucous membrane is affected, it can cause pain and greatly restrict the ability to eat; these lesions may occur before or after skin lesions. 

 

The symptoms are anticipated to resolve spontaneously after 4 weeks from the start of the condition (or up to 6 weeks in cases of severe disease).

Diagnosis:

The diagnosis of acute erythema migrans (EM) is often established by evaluating the patient’s history and thorough physical examination of their clinical symptoms. Skin biopsies are helpful in confirming the diagnosis when there is uncertainty. Direct immunofluorescence studies may be necessary to rule out the presence of autoimmune blistering disease.

Differential diagnosis:

• Urticaria
• Viral exanthem
• Stevens-Johnson syndrome
• Fixed drug eruption
• Bullous pemphigoid
• Paraneoplastic pemphigus
• Polymorphous light eruption
• Rowell syndrome (erythema multiforme-like lesions in systemic lupus erythematosus)

Management:

Treatment is frequently unnecessary as episodes are generally self-limiting without any persistent complications. However, the presence of ocular involvement should always result in a referral to an ophthalmologist due to the potential for more severe consequences.

Management of symptomatic mild cases:

• Itch: To relieve itch or discomfort caused by skin lesions, oral antihistamines and/or topical steroids might be used.
• Pain: For mild mucosal involvement, oral washes containing antiseptic or local anesthetic might be used to relieve pain.

Additional therapies are dependent on the underlying cause:

• Infection: treat precipitating infections appropriately (notice that treating HSV does not change the course of a single episode of erythema multiforme significantly). 
• Offending medication: stop any offending medication and avoid in future.

Severe mucosal disease:

• Admission to the hospital might be necessary to support oral intake.

Chronic illness:

• A minimum duration of 6 months of continuous oral antiviral treatment (usually acyclovir/aciclovir), regardless of whether a definite cause has been determined.
• Achieving remission might be challenging and may necessitate trying a longer course of treatment or a different antiviral medication.

 

 

Written by:

Mashael Alanazi, Medical Student.

Revised by:

Maee Barakeh, Medical Student.

Resources:

DermNet

UpToDate

Topical corticosteroid withdrawal is an infrequent rebound reaction that happens in patients who have excessively used topical steroids and occurs following cessation.

This condition is typically a result of long-term application of topical corticosteroids with moderate to high potency. Withdrawal symptoms might manifest as skin burning, itching, redness, scaling, swelling, papules, or pustules.

Etiology:

The etiology of topical steroid withdrawal may be explained by the following mechanisms:

• Tachyphylaxis, which is a decrease in response, occurs with continued application, resulting in the need for higher doses.
• Patients with atopic dermatitis who do not respond well to topical steroids have an upregulation of glucocorticoid receptor b.
• Following the withdrawal of topical steroids, keratinocytes continue to suppress the formation of self-cortisol.
• Topical corticosteroids induce vasoconstriction, however, upon discontinuation, there is a rebound effect of vasodilation due to an increase in the release of nitric oxide, resulting in skin redness (erythema).
• Disruption of the barrier leads to a subsequent release of cytokines, triggering a cascade of immune responses, after the anti-inflammatory effects of topical corticosteroids are stopped.

Clinical manifestations:

The withdrawal symptoms might begin anytime from 48 hours to more than 3 months after discontinuation. 

Withdrawal generally manifests in four distinct stages:

• Typically, a few days after stopping the treatment, there is a sudden eruption of intensely red and oozing skin, which may spread to places that were not previously treated.
• The skin experiences dryness and itchiness accompanied by shedding, also known as desquamation.
• The skin begins to regenerate, although it becomes more sensitive and may experience occasional flare-ups.
• The skin returns to the state that it was before topical corticosteroid cessation. The duration of the recovery process can range from several weeks to several years.

Symptoms: 

• Severe itch
• Intense itching
• Burning pain 
• Insomnia
• Depressed state
• skin hypersensitivity
• Intolerance to emollients.

Skin characteristics:

• Erythematous skin
• Elephant wrinkles refer to the thicker skin with decreased flexibility that typically affects the extensor surfaces of the body.
• The red sleeve sign refers to the presence of erythema (redness) on the limbs, but the palms and soles are not affected.
• The headlight sign is characterized by redness (erythema) across the face, but specifically excluding the nose and the area around the mouth (perioral skin).
• Skin shedding (desquamation)
• Edema
• Exudate.
• Telangiectasia
• Papules with or without nodules
• Pustules. 

Diagnosis:

One of the challenges is determining whether the observed skin reaction is a result of discontinuing topical corticosteroids or a deterioration of the underlying skin condition for which the steroids were given.

The diagnostic criteria for topical corticosteroid withdrawal lack consensus. However, recent literature highlights the following key features: 

• Frequent and prolonged topical steroid use on the area of initial eruption
• Frequent topical steroids  use on the face or genital area
• Sensation of burning or itching

Often associated with:

• Atopy history, particularly atopic dermatitis
• History of using oral prednisone to treat skin conditions
• sensitivity 
• Skin shedding 
• Swelling, particularly in the eyelids or ankles, and the presence of ‘elephant wrinkles’ on the back of the elbows and front of the knees (extensors).
• Red sleeve sign.

Patch testing is a valuable tool for ruling out contact dermatitis caused by topical corticosteroids, cream excipients, or other topical treatments such as emollients. However, this can be challenging if there is not enough healthy skin available for testing.

Histology is not a reliable method for diagnosing topical corticosteroid withdrawal because the histological signs it presents, such as epidermal atrophy, spongiosis, and parakeratosis, are not specific enough.

Management:

General measures:

• Emollients and moisturizers.
• cold compresses, the use of ice, and the administration of gabapentin for burning pain.
• Antihistamines are used to alleviate itching.
• Pain management with simple analgesic.

Specific measures: 

• The primary treatment approach is discontinuing the use of topical corticosteroids, while closely monitoring for any rebound reactions. 
• There is controversy around tapering vs abrupt withdrawal.
• Gradually reducing the dosage of oral corticosteroids.
• Dupilumab should be taken into consideration for people with atopic dermatitis.
• Prevention and treatment of any subsequent infection.
• Phototherapy.
• Immunosuppressants. 

Prevention:

• Gradually decrease the frequency and potency of topical corticosteroids once the inflammatory skin conditions have resolved.
• Avoid prolonged use of strong topical corticosteroids on the face.
• Reduce the length of continuous and prolonged corticosteroid treatment, for example, to less than 2 weeks. Certain disorders, including vulval lichen sclerosus, may require a therapy duration beyond 4 weeks in order to optimize the favorable response.
• Decrease the strength and frequency of topical steroid usage from daily to twice weekly after 2-4 weeks of treatment.

Finally, atopic dermatitis and other skin disorders should be well treated despite concerns about the risk of topical corticosteroid withdrawal, since a considerably higher proportion of patients react to effective topical steroid use than have withdrawal symptoms.

Written by:

Mashael Alanazi, Medical student

Revised by:

Maee Barakeh, Medical student

References:

DermNet

What is Cutis verticis gyrate?

 Cutis verticis gyrata is an uncommon, congenital, or acquired scalp disorder characterized by an overgrowth of the scalp skin resulting in convoluted folds and deep furrows that mimic the surface of the cerebral cortex. It is more prevalent in males than females. The majority of primary cases develop after puberty and usually occur before the age of thirty. Some secondary types of cutis verticis gyrata may be present at birth.

 

Cause of Cutis verticis gyrata

Cutis verticis gyrata is caused by the proliferation of the scalp skin. It is categorized as:

• Primary essential cutis verticis gyrata with no other related abnormalities. Primary indicates that the etiology of the disease is unknown.
• Primary nonessential cutis verticis gyrata is linked to neuropsychiatric illnesses such as epilepsy, seizures, cerebral palsy, and ophthalmologic abnormalities.
• Secondary cutis verticis gyrata can be caused by many disorders that alter scalp structure, such as:

1. Acromegaly
2. Melanocytic naevi (moles)
3. Birthmarks, including connective tissue naevus , fibromas and naevus lipomatosus
4.  Inflammatory conditions include eczema, darier disease, psoriasis, folliculitis, impetigo, atopic dermatitis, and acne. 

 

Clinical features of Cutis verticis gyrata

Cutis verticis gyrata usually affects the center and back of the scalp, although in certain cases it can affect the entire scalp. The folds feel soft and spongy. It cannot be rectified by pressure. The skin color is unaffected. The number of folds might range from two to over ten. Folds in primary cutis verticis gyrata are usually symmetric, while those in secondary cutis verticis gyrata are asymmetric.

 

Diagnosis of Cutis verticis gyrata

Cutis verticis gyrata is typically a clinical diagnosis.
Investigations for neurological diseases or underlying disorders may involve:

• skin biopsies
• radiography, such as MRI.

 

Treatment of Cutis verticis gyrata

Cutis verticis gyrata therapy includes maintaining adequate scalp hygiene to prevent secretions from accumulating in the scalp’s furrows. For cosmetic reasons, definitive surgical treatment may be requested. Secondary cutis verticis gyrata is treated based on the underlying condition.

 

Prognosis of Cutis verticis gyrata

Cutis verticis gyrata is a progressive condition. It is mostly bothersome because of its cosmetic appearance. It is rarely complicated by melanoma growing within a melanocytic naevus.

 

 

Written by:

Atheer Alhuthaili , Medical Student. 

Revised by:

Maee Barakeh, Medical Student

References:

DermNet

UpToDate

Medscape

Pityriasis alba is a skin condition that primarily affects people between the ages of three and sixteen in children and young adults. It is common worldwide with a prevalence in children of around 5%. It affects males and girls female equally. Pityriasis alba hypopigmentation is more noticeable and possibly more prevalent in black skin types than in white skin types.

Etiology: 

The etiology of pityriasis alba is idiopathic. It is usually associated with atopic dermatitis and dry skin. It frequently appears after sun exposure, maybe because the afflicted spots become more noticeable due to surrounding skin darkening. Ongoing research about the relationship between pityriasis alba and the following factors: UV radiation, insufficient or excessive bathing, low levels of copper, and Malassezia yeasts.

Clinical features:

The patients will usually present with 0.5 to 2 cm multiple hypopigmented patches or thin plaques on the cheek and chin. The patches could be oval, round, or irregular in shape with poorly defined edges. Usually, the patients will have absent or minimal itch. The dryness and scaling are more noticeable in the winter, while the hypopigmentation is more noticeable in summer.

Pityriasis alba patches undergo several stages:

1. The appearance of scaly pink with just a palpable surface.
2. The hypopigmentation stage with fine surface scale.
3. The post-inflammatory hypopigmented macule/ patch with no scale.
4. Resolution of the lesion. 

Diagnosis:

The diagnosis is usually clinical, and the investigations are done to rule out other differential diagnosis:

• Wood lamp: No enhancement in the cases of pityriasis alba.
• Scrapings for mycology: negative in the cases of pityriasis alba.
• Skin biopsy: Usually not indicated, would reveal spongiotic dermatitis and melanin reduction.

A dermoscopy of pityriasis alba will reveal, a poorly defined pale area, white structureless areas, superficial white scale, and normal hair color. 

Management:

Asymptomatic pityriasis alba requires no treatment. A moisturizing cream to improve the dryness, and a mild topical steroids will reduce redness and itchiness if present. It has been observed that calcineurin inhibitors, such as tacrolimus ointment and pimecrolimus cream, speed up the return of skin color and maybe just as effective as hydrocortisone.

Psoralen + UVA photochemotherapy is used in severe situations, this treatment may aid in repigmentation; nevertheless, the likelihood of recurrence following treatment discontinuation is considerable. Laser therapy can be effectively treated with a twice-weekly, 308-nm excimer laser treatment for 12 weeks. 

Prevention:  

Sunscreen use could be utilized to reduce the development of pityriasis alba.

Outcome: 

Pityriasis alba usually goes away in a year, although it might take anything from a few months to two or three years. The color gradually reverts to its original state.

Written by:

Mohammed Alahmadi, Medical Student. 

Revised by:

Maee Barakeh, Medical Student. 

References:

DermNet.

Fitzpatrick’s Color Atlas and Synopsis of Clinical Dermatology.

Dermatology by Bolognia.

What is Tinea Versicolor?

Tinea versicolor is a commonly occurring, benign, superficial cutaneous fungal infection that is typically characterized by patches and macules on the back and chest that are either hyper- or hypopigmented. It is caused by Malassezia species. Despite the availability of efficient oral and topical treatment methods, disease recurrence is frequent.

 

Epidemiology of Tinea Versicolor

Tinea versicolor occurs worldwide, with a higher occurrence in tropical climates. Adolescents and young adults are the most common age groups to develop tinea versicolor. It can also impact children and infants.

 

Risk Factors for Tinea Versicolor

There are various risk factors associated with this disease. These risk factors include exposure to hot and humid weather, hyperhidrosis, use of topical skin oils, genetic predisposition, immunosuppression state, malnutrition, corticosteroid usage, and Cushing disease. It may clear in the winter and reoccur each summer.

 

Cause of Tinea Versicolor

Tinea versicolor does not result from a dermatophyte infection. It is considered non-contagious. The causative organism is a Malassezia species. It is a component of the normal skin flora, but it can cause the disease when it transforms into its pathogenic hyphal form. The reasons for the transformation of tinea versicolor are likely to be multifactorial.

 

Clinical Features of Tinea Versicolor

Tinea versicolor is typically asymptomatic; some complain of mild pruritus, with the main issue being its appearance.Tinea versicolor lesions are characterized by hyperpigmented, hypopigmented, or erythematous patches, macules, or thin plaques with a mild scale. To demonstrate this scale, the skin surface may need to be scratched. These lesions are usually small (<15 mm) and range in color from coppery brown, paler than the surrounding skin, or pink. The most typical areas of involvement are the upper trunk and proximal upper extremities. Less frequently, faces (common in children) or intertriginous areas are affected.

 

Diagnosis of Tinea Versicolor

Tinea versicolor is usually diagnosed clinically. Dermatoscopy and Wood’s lamp examination may show signs suggestive of tinea versicolor but do not confirm the diagnosis. Dermoscopic examination reveals fine-scale, nonuniform pigmentation within lesions and perilesional hyperpigmentation or hypopigmentation. Wood’s lamp examination exhibits yellow to yellow-green fluorescence in certain patients. The KOH preparation findings in tinea versicolor are considered diagnostic. It shows hyphae and yeast cells that resemble spaghetti and meatballs.

 

Management of Tinea Versicolor

The management of Tinea versicolor can be summarized into a few fundamental aspects:

1:Patient education

2: Topical antifungals, which are considered first-line therapy, including Selenium sulfide, zinc pyrithione, azoles (miconazole or ketoconazole), or allylamines (terbinafine)

3: Oral antifungals are only for infections that are severe, extensive, or resistant to topical treatment (not commonly used in children). Oral itraconazole and fluconazole are the recommended oral medications.

 

Recurrence of Tinea Versicolor

Tinea versicolor has a high recurrence rate. Preventive treatment with topical or oral medication administered intermittently is required to avoid recurrences in most cases.

 

 

Written by:

Atheer Alhuthaili , medical student. 

Revised by:

Maee Barakeh, medical student.

References:

Bolognia textbook of dermatology.

DermNet.

UpToDate.

Medscape .

Orf is a skin infection caused by parapox virus, a zoonotic contracted from goats and sheep. Because the condition causes crusts and scabs around the mouth, nose, teats, and other areas, it is also known as contagious pustular dermatitis. The disease lasts for roughly six weeks, and it is extremely contagious.

 

Cause and Mode of Transmission: 

Direct inoculation of contaminated material, frequently through an already-existing wound or scratch, results in lesions in humans. Shearers, freezer workers, sheep producers, and anyone bottle-feeding a lamb run the danger of contracting orf. Youngsters may potentially get it from playing in a sheep shed or on contaminated pasture. There have been reports of human orf following unintentional contact with animal-targeted orf virus vaccination. It is not typically spread from person to person, however sporadic reports of this have occurred.

 

Clinical Features:

The incubation period lasts from 5-6 days. Patients usually present with a 2-3 cm solitary small, firm, red lump that enlarges to form a flat-topped, blood-tinged pustule or blister on the forearms, hands, and fingers. Large lesions could be observed in immunocompromised individuals. 

Typically, making an incision through the skin will reveal firm, red tissue beneath, despite the appearance of pus from the skin. In the early stages, the orf lesion is frequently sensitive and irritating. Lymphangitis and lymphadenopathy of the inner side of the elbow and/or under the arm are not uncommon. These features could be associated with mild fever.  

 

Diagnosis:

A clinical diagnosis of orf is typically made in a person who has experience working with sheep or goats. PCR can be used to confirm the infection in vesicular fluid, skin biopsies, or viral swabs. Electron microscopy can be used to identify it as well. 

 

Management:

Most of the time, no special care is required because orf resolves on its own in roughly six weeks. While it is extremely rare, the lesion should be covered to avoid infecting the surrounding area or other persons. Shave excision is one method of removing large lesions. Antibiotics are the appropriate treatment for secondary bacterial infections. A few cases of orf have been found to respond well to imiquimod cream.

 

Complications: 

The complications of orf include secondary bacterial infection, erythema multiforme, toxic eythemas, and rarely pemphigoid.

 

Prevention:  

Farmers who raise sheep and goats should be mindful of the risk of orf and handle the animals especially lambs and young while using non-porous rubber gloves with washing hands. It is advised to vaccinate the herd using a live virus in the event of a severe orf outbreak.

 

 

Written by:

Mohammed Alahmadi, Medical Student. 

Revised by:

Maee Barakeh, Medical Student. 

References:

DermNet.

Fitzpatrick’s Color Atlas and Synopsis of Clinical Dermatology.

Andrews’ Diseases of the Skin: Clinical Dermatology.