Viral Skin Infections PDF

Viral Skin Infections Dr. Abdulrahman Omar ABHS, Dermatology 5th grade – College of medicine University of Duhok Viral Warts HPU ØCaused by Human papillomavirus (HPV), a DNA virus that infect the epithelia of skin or mucosa, affecting people of all...

Viral Skin Infections Dr. Abdulrahman Omar ABHS, Dermatology 5th grade – College of medicine University of Duhok Viral Warts HPU ØCaused by Human papillomavirus (HPV), a DNA virus that infect the epithelia of skin or mucosa, affecting people of all ages and all races, But it is most common in children and young adults. ØThere are more than 150 genotypes of HPV, these vary in their specificity for different anatomical site, causing different skin lesions: 0111412,4 HPV 1, 2 and 4, are found in common and planter warts. HPV 3, 10 is found in plane warts HPV 6, 11, 16 and 18 are most common in genital warts. and oral warts 10,180 6111  Genital warts occurs mostly by intimate contact, while non-genital may occur via direct skin-skin contact or indirectly through contaminated surfaces or objects (e.g. swimming pool, gym), Autoinoculation may also occur. The majority of warts will regress spontaneously within 1–2 years. After clearance, re-infection with the same HPV type appears to be uncommon. Persistent infection with sexually transmitted high-risk mucosal types, mostly HPV 16 and 18, cause all cervical and most anal cancers, a subset of vaginal, vulvar, penile and oropharyngeal cancers, and rarely cancers of the digits.  112140 Clinical Patterns: circumsuffrported Common wart (Verruca vulgaris) These are circumscribed, firm, papules with “verrucous” hyperkeratotic surfaces. They occur singly or in groups. Generally, they are associated with little or no tenderness and occur most commonly on the dorsal aspects of the fingers and hands.  Filiform warts, a variant of common wart, show thread-like, keratinous projections, occur mostly on the face and scalp.  Plantar wart (verruca plantaris): Usually presented as painful, deeply embedded papules on the sole of the foot, (esp. on pressure points). They may be single or multiple. Usually are covered with a rough hyper- keratotic surface which when removed with a scalpel, black dots (thrombosed capillaries) become apparent. Mosaic wart is a plaque of closely grouped warts. DDx: Corn, Callus. 068 Plane or Flat wart (verruca plana): 3.10 Are slightly elevated, flat, smooth papules. Usually skin colored but may pigmented. The face and the dorsum of the hands are affected most commonly. Numbers range from few to 100s. Koebner’s phenomena (i.e. occurrence of new lesions at trauma sites) is positive, like in the common wart. DDx: lichen planus. Acne vf r  Anogenital wart (Condylomata acuminata): Affect vulva, vagina, cervix, penis, scrotum, perianal skin, and anal canal. lesions are well-defined papules, On mucosal surfaces, they are often macerated and appear pale, but on dry skin, they can become more obviously hyperkeratotic. May be small or coalesce into cauliflower-like masses.  Oral warts Warts can develop on the lips, in the oral cavity, and in upper respiratory tract and are usually regarded as STD. The low-risk genital HPV (6,11) types are the usual cause, (less commonly, Multiple mucosal warts extending to other types). the vermillion border, where they become highly keratinized Treatment: Routine treatment of every wart is unnecessary. Explain that self resolution may occur. More than two thirds resolve within 2 years Topical applications: kemt0y Keratolytics (salicylic acid and lactic acid) for common and plantar warts, Trichloroacetic acid (TCA) may also be used. Retinoids may be useful for flat warts. 8 Podophyllin is used for anogenital warts. Imiquimod cream is also effective. Surgical methods: Cryotherapy by liquid nitrogen is a standard method for warts. Curettage (especially for Filiform warts and exophytic lesions) Electrosurgery Cautery Surgical excision , Laser Surgery ( especially for recalcitrant warts). Herpes Viruses Herpes viruses belong to Herpesviridae which is a large family of DNA viruses. There are 8 distinct viruses in this family known to cause diseases in human: HHV -1 (HSV -1) à Herpes Labialis. HHV -2 (HSV -2) à Herpes Genitalis. HHV -3 (VZV) àChickenpox and Herpes Zoster. HHV -4 (EBV) àInfectious Mononucleosis. HHV -5 (CMV) àInfectious Mononucleosis -like syndrome. HHV -6 àRoseola Infantum. HHV -7 àPityriasis Rosea. HHV -8 àKaposi's Sarcoma. Herpes Simplex Viruses (HSV-1 & HSV-2) (Synonyms: Herpes Labialis, Cold Sore, Fever Blister, Herpes Genitalis) HSV produce primary and recurrent vesicular eruptions that favor the orolabial and genital regions. HSV-1: cause extra-genital infection, HSV-2: cause genital disease. However either virus can affect any area of skin or m.membrane. Pathogenesis Transmission of HSV can occur during asymptomatic periods of viral shedding. HSV-1 is spread primarily through direct contact with contaminated saliva or lesions secretions, while HSV-2 is spread primarily by sexual contact. Virus replicates at the site of infection and then travels by retrograde axonal flow to the nerve ganglia, where it establishes latency until reactivation  Clinical Features Primary HSV-1 infection Asymptomatic infection is common. Symptoms typically occur within 3 to 7 days after exposure. A prodrome of tender lymphadenopathy, malaise, anorexia, and fever often occurs before the onset of mucocutaneous lesions, which may be preceded by localized pain, tenderness, burning, and tingling. Painful, grouped vesicles appear on an erythematous base followed by erosions or ulcerations with a characteristic scalloped border.  Primary HSV-2 infection Frequently asymptomatic, but can present as extremely painful erosive balanitis, vulvitis or vaginitis. Presents with constitutional symptoms and painful grouped vesicles in genitalia à progress to pustules, crusting and tender ulcers, ± painful lymphadenopathy, cervicitis, urethritis, proctitis. The presence of more extensive local involvement, regional lymphadenopathy, and fever generally distinguishes primary herpes infection from recurrent disease. Recurrent infection of both HSV-1 & HSV-2 The lesions usually occur on the same place each time and may be precipitated by: 1. Fever. 2. Respiratory tract infection. 3. exposure to sun. 4. Menstruation, stress. 5. Trauma. Primary herpetic gingivostomatitis Recurrent Genital herpes of the penis Cutaneous herpes simplex  Other Clinical Presentations of HSV Infection: Eczema herpeticum Occur in patients with atopic dermatitis and other skin disease with impaired skin barrier Rapid, widespread , Monomorphic, discrete, 2–3 mm punched-out erosions with hemorrhagic crusts. Mostly occur in areas of active or recently healed atopic dermatitis, particularly the face. The disease in most cases is a primary HSV-1 infection. The severity of infection ranges from mild to fatal. Treatment: Eczema herpeticum of the young infant is a medical emergency, treated by acyclovir 5-10mg/kg 8 hourly IV. In adult, acyclovir 800mg 3 times daily for 10 days. Eczema herpeticum in baby with atopic dermatitis  Herpetic whitlow It is the cutaneous herpetic infection presented with Pain, swelling, and clustered vesicles on a digit. Often in young children ,usually due to HSV-1. In dental and medical personnel who did not use gloves. It results from direct virus inoculation of the involved digit through the abraded skin. Investigations: None are usually needed, but Tzank smears (Multinucleated giant cells present in scraping of mucocutaneous lesions), viral culture, PCR, or skin biopsy may be needed in doubtful cases. Complications HSV Infection: 1. Secondary bacterial infection. 2. Erythema multiforme: may follow recurrent herpes simplex infections. 3. Recurrent dendritic ulcers: leading to corneal scarring. 4. Disseminated herpes simplex: in newborns or immunosuppressed patients, resulting in severe illness. 5. Herpes encephalitis and meningitis, can occur without any cutaneous clue. Management: The disease is usually self limited and no much interference is required. A cool water compress or surgical spirit dabbing and topical antibacterial cream is sufficient for occasional mild recurrent attacks. More severe and frequent attacks may require the application of acyclovir cream (5 times daily for 5 days) with the first sign of recurrence. Oral acyclovir (200mg 5 times daily for 5 days) is more effective and can be used for widespread or systemic involvement. Famciclovir and valcyclovir as alternatives.  Varicella (chickenpox) Is a highly contagious viral infection. Transmission occurs via droplets or vesicular fluid. Patients are contagious from 2 days before onset of the rash until all lesions have crusted. This is important for isolation An attack of chickenpox usually confers lifelong immunity. After it has produced chickenpox, varicella-zoster virus becomes latent in dorsal root ganglia. The incubation period averages 14 days, with a range of 9 to 21 days.  The prodromal symptoms in children are absent or consist of low fever, headache, and malaise, which appear directly before or with the onset of the eruption. Symptoms are more severe in adults. On the skin, lesions of different stages(papules, vesicles, pustules, and crusts) are present at the same time in any given body area. New lesion formation ceases by day 4 and most crusting occurs by day 6. The rash begins on the face and trunk and spreads to the other parts of the body. Oral lesions (enanthem) and scalp lesions are highly suspicious The lesion starts as a 2-4 mm red papule that develops an irregular outline (rose petal) and a thin-walled clear vesicle appears on the surface (dewdrop). This lesion, “dewdrop on a rose petal” is highly characteristic for varicella. Vesicles on top of papule  The complications of varicella are secondary bacterial infection, encephalitis, Reye’s syndrome, pneumonia and Scarringà (if lesions secondary infected or excoriated). Treatment: üIn healthy children, varicella is generally benign and self-limited. Cool compresses, calamine lotion locally and oral antihistamines may relieve itching.. üAntipyretic like Paracetamol (excluding aspirinà Reye’s syndrome). üOral antibiotic against Strep. and Staph. like cephalexin is indicated for secondarily infected lesions. üAdult chickenpox, in addition to above, should be treated with oral acyclovir (800mg 5 times daily for 7 days). Same dose for shingles 20 mg/kg/dose for children Chickenpox  Herpes Zoster (HZ) (Shingles) Varicella and shingles both are produced by the same virus. Varicella results from contact of a non-immune person with this virus, whereas shingles occurs in persons who have had previous varicella, either clinically or subclinically. HZ is caused by reactivation of a latent infection in either a spinal or a cranial sensory ganglion. On reactivation, the virus spreads from the ganglion along the corresponding sensory nerve to the skin.  Precipitating factors for reactivation: Age, Immunosuppression ( drug, disease), Emotional upset and Radiation. It occurs largely in adults, particularly old age, but it can occur in children (usually with a mild course). Pain, tenderness, paresthesia, generally localized to the dermatome, precedes the eruption by 4-5 days and may be accompanied by fever, headache, and malaise. Regional lymphadenopathy may be present. The pain may simulate pleurisy, MI, renal pain, abdominal disease, or migraine headache.  Patient with HZ can transmit the virus and cause chicken pox in non-affected individuals. Eruption consists of grouped vesicles on (erythematous and edematous) inflammatory bases, arranged along the course of a sensory nerve (in an interrupted or a continuous band). HZ is characteristically unilateral, dermatomal. Thoracic region is affected in 2/3 of cases. It is possible, though very unusual, to have two or three episodes in life time.  Cranial nerve syndromes: these are special variants of herpes zoster. Ø Herpes zoster ophthalmicus: involvement of the ophthalmic division of trigeminal nerve can lead to corneal ulcer and scarring. ØRamsay Hunt syndrome: when the geniculate ganglia are affected causing unilateral facial nerve palsy accompanied by vesicular rash on the ear or in the mouth with unilateral loss of taste sensation on the anterior 2/3 of the tongue. Complications 1.Secondary bacterial infection of skin lesions is common. 2.Post herpetic neuralgia: persistent neurologic pain, after the acute episode is over, is most common in the elderly. 3.Meningoencephalitis, visceral involvement (pneumonitis, hepatitis, etc), or cutaneous dissemination may occur in immunosuppressed patients. 4.Corneal ulcer and scarring in herpes zoster ophthalmicus. 5.Motor nerve weakness (uncommon). Treatment: Rest, NSAIDs, and soothing lotions such as calamine. Secondary bacterial infection should be treated appropriately. Systemic antiviral therapy should be given to all patients if diagnosed in the early stage (within first 72 hours) of the disease. Oral acyclovir (800 mg 5 times daily for 7 days). Famciclovir and valacyclovir are also effective. For established post-herpetic neuralgia, systemic gabapentin, carbamazepine, or amitriptyline may be used. Topical capsaicin cream or regional infiltration with lidocaine may be tried.  Molluscum Contagiosum (MC) Pox virus infection, a common, self-limited condition in children. It also occurs in adults, usually as STD. Giant MC can occur in immunocompromised hosts(e.g HIV). Transmission is via skin-to-skin contact, touching a contaminated fomites and sexually. May further spread by autoinoculation, scratching (Koebner's phenomenon) The incubation period range from 2-6 weeks, often several members of one family are affected. Sites: can occur anywhere in the body except the palms and soles, in children (face, trunk, axilla and extremities), in Adults (pubic and genital area) are mostly affected.  The lesions may be few or many. The individual lesions begin as smooth, shiny, white or pink, dome-shaped papule. They grow slowly up to 0.5 cm, with time the center become soft and umbilicated and may contain a cheesy core. If one lesion is pustule (inflammatory) so the immune system is stimulated and thus other lesions will resolve soon after Treatment Many simple destructive measures cause inflammation and then resolution. (For e.g. squeezing out the lesions with forceps, piercing them with needle, and curettage). Cryotherapy, wart paints and topical imiquimod may also be helpful. These measures are fine for adults, but for young children nott usually needed as Mollusca are self-limiting, usually clear in 6–9 months doing nothing is often the best option. Orf (Ecthyma Contagiosum) A zoonotic infection caused by orf virus (parapoxvirus) that contracted from sheep and goats. Most commonly seen on the hands and fingers of shepherds, or their wives who bottle-feed lambs, butchers, vets and meat porters. The lesion develops 3–7 days after contact with an infected animal or animal carcass, and progress through six stages: ( maculopapular, targetoid, weeping nodule, regenerative, papillomatosis, and regression). May be accompanied by lymphangitis, lymphadenopathy, malaise, fever. Differential Dx: Milker’s nodule, Pyogenic granuloma and Herpetic whitlow. Complications: Secondary bacterial infection. Erythema multiforme is a well‐recognized sequel of orf infection. Giant orf or widespread lesions can occur in persons with impaired immunity. Bullous-pemphigoid like eruptions may rarely develop. Management üNo active treatment is required, the lesions heal after 3–6 weeks, but topical antibiotic can be used to prevent secondary bacterial infection. üImmunocompromised patients may require debridement, antiviral cidofovir cream, or imiquimod topical immunomodulatory therapy. Orf