Introduction:
Our skin is the body’s largest organ and has different functions, including protecting and covering the body. Viral infections cause skin lesions in three ways: direct inoculation spread from a specific internal site or systemic disease. The skin lesions can result from direct viral replication or the host response to the virus. The treatment will depend on the type of lesion and the severity of the infection.
What Are the Different Viral Infections of the Skin?
The skin infection caused by a virus can be primary or secondary. The primary skin lesions are present at the onset of disease, while the secondary skin lesion occurs due to the progress of the disease (like rubbing, scratching, etc.). The major primary viral infections of the skin are caused by a poxvirus, herpes simplex virus (HSV), and papillomavirus.
The smallpox virus with significant mortality has been eradicated with the help of vaccines. The viral infection of interest caused by the poxvirus family is molluscum contagiosum. The herpes virus causes cold sores and genital herpes. They are incurable, and the virus remains latent in the neural ganglion. They are activated by specific triggers like stress, fever, sun exposure, etc. Varicella-zoster causes chickenpox in children, which can get reactivated and present as a herpes zoster (shingles) in adults. Reactivation is mainly due to the immunocompromised state in the individual.
The secondary viral infections are caused by paramyxovirus, togavirus, retrovirus, picornavirus, and parvoviruses.
What Are the Different Signs and Symptoms?
Herpes -
The cutaneous manifestations of herpes include:
-
Genital herpes.
-
Eczema herpeticum (extensive cutaneous vesicles formed on a pre-existing skin lesion).
-
Herpes gladiatorum (common in contact sports).
-
Herpetic whitlow (a lesion on the thumb or finger).
-
Lumbosacral herpes (recurrent lesion in the lower back and buttocks).
-
Erythema multiforme (hypersensitivity triggered by infections such as HSV).
Molluscum contagiosum -
The characteristic papules (elevated area less than 5 cm in diameter) commonly appear on the children's face, trunk, and limbs. They are painless but cause severe itching. They are flesh-colored at first and later become red. It appears on the adult's genitals, abdomen, and inner thighs but not the palms and soles. It is mostly present for months. Sometimes it can last longer upto four or five years in immunocompromised individuals and it does not cause scarring.
Varicella-Zoster -
It includes symptoms such as fever, malaise, and maculopapular lesions, followed by vesicles that rupture and form crusts. The infectivity period is one week which starts two days before the appearance of lesions to crusting of the lesions.
Herpes Zoster -
It is seen in older people, usually greater than 50 years of age. The disease presents as a painful vesicular rash that is localized compared to diffused lesions in varicella. The rash is preceded by numbness, burning sensation, increased sensitivity to pain. It usually affects the ophthalmic branch of the fifth cranial nerve. If the seventh cranial nerve is involved, Ramsay hunt syndrome (facial palsy, blisters in the external auditory meatus, dizziness) may be present in some individuals.
Measles and Rubella :
Usually, they show symptoms like malaise, fever, and a maculopapular rash. They are discrete and spread from head to trunk to extremities. In the case of measles, the characteristic presentation includes fever, sore throat, cough, coryza (inflammation of mucous membrane in the nose), conjunctivitis, and oral koplik’s (bluish-white raised lesions on the buccal mucosa) spots. The infectivity period lasts four days before and four days after the rash. Rubella presents itself as a rash similar to measles but milder than measles. Along with this, it also shows low-grade fever and lymphadenopathy.
Human Papillomavirus -
The skin manifestation of HPV differs according to the epithelium it affects. The virus is usually spread by direct contact or by touching an object that has the virus. Plantar, flat, and butcher warts are often found on the hands and feet. Genital warts (condyloma acuminatum) are sexually transmitted. These viruses have also been associated with cervical cancer.
Coxsackievirus -
It causes hand, foot, and mouth disease. Oral vesicles, tender cutaneous lesions, and fever are usually seen. The coxsackievirus causes herpangina. It causes fever and painful oral lesions.
How to Diagnose Them?
Herpes Simplex Virus -
It can be diagnosed by clinical signs and symptoms, viral culture, serology, polymerase chain reaction (PCR), Tzanck smear, or direct fluorescent antibody (DFA). However, a rapid test like the Tzanck smear cannot differentiate between the herpes viruses, including varicella. Viral culture remains the gold standard for diagnosis.
Herpes Zoster -
The diagnosis involves clinical vesicular rash in the thoracic, cranial nerve V and cranial nerve VII region. Viral cultures and DFA can also be employed.
Human Papillomavirus -
Clinically warts and hyperkeratotic papules with tiny black dots (blood clots in the capillaries) are present. Testing of the cervical cytology or biopsy is advised. There are no approved tests for the other sites.
Measles and Rubella -
Diagnosis of measles involves detecting IgM antibodies, ribonucleic acid (RNA) by polymerase chain reaction (PCR). IgM antibody detection is done for rubella in adults, and serology or virus isolation is done in congenital cases.
Coxsackievirus -
The diagnosis is based on the oral vesicles and tender cutaneous nodules clinically. Viral culture, PCR, or serology tests can also be used.
What Is the Treatment for the Viral Infections of the Skin?
Herpes Virus - The virus is not curable and symptomatic treatment is given so that the virus does not spread and the duration of the clinical symptoms are reduced.
Measles and Rubella - Treatment involves giving supportive care. Giving vitamin A supplementation is associated with decreased morbidity and mortality in the case of measles. MMR vaccine is used for the prevention of the disease. It is given as post-exposure prophylaxis to high-risk patients within 72 hours.
Mollascum Contagiosum - It is generally self-limiting. In immunocompromised individuals and recurrent cases, treatment may be necessary. It includes cryotherapy (extreme cold produced by liquid nitrogen gas to destroy the cells), curettage, laser therapy, and topical treatments. Oral Cimetidine and intravenous Cidofovir can also be used.
Human Papillomavirus Papilloma Virus - The treatment involves cryosurgery, electrodesiccation (drying of tissue by using high-frequency electric current), curettage, and topical agents to remove warts. An HPV vaccine is used in the prevention of the disease.
The treatment for coxsackievirus is generally supportive care.
Conclusion:
The skin lesions are characteristic of a particular viral infection. This helps the doctor arrive at a better diagnosis quickly and start the treatment before getting confirmed laboratory test reports, which may require additional time. However, vaccines and new drugs are promising achievements in curing these diseases.
