Viral Skin Infections

Infectious Papules: These infectious dome-shaped papules are caused by a pox-virus. They have a central dimple in which often typical whitish cheesy material can be seen, resembling a little white ball.

Affected Areas: Molluscum normally occurs in small children in areas of warmth, moisture, and friction such as the armpits and the groins, and on the face.

Self-Limiting Nature: Generally, they are self-limiting and will disappear within a year without treatment. If they persist for a longer time or cause complaints, they may be treated.

Adult Occurrence: When they occur in adults, particularly with multiple and large lesions, there may be immunosuppression.

Diagnosis

• Microscopic Examination: The central plug of material, composed of virus-laden cells, may be shelled out from a lesion (see Treatment) and examined under the microscope with 10% potassium hydroxide or Wright or Giemsa stain.
• Antibody Detection: Specific antibody against molluscum contagiosum virus is detectable in most infected individuals.

Treatment

• Self-Limited Nature: Molluscum contagiosum is a self-limited disease; the average attack lasts 6–9 months. However, lesions can persist for years, spread to distant sites, and may be transmitted to others. Affected patients should avoid shared baths and towels until the infection is clear.
• Pricking and Content Removal: Prick the center with a sharpened matchstick and press out contents.
• Curettage or Lancing: Curettage with a sharp curette or lance with a pin.
• Antiseptic Application: Use betadine solution or scrub after the above until dry.
• Caustic Treatment:
• Caustic Pencil (Silver Nitrate): For small molluscum.
• Caustic Agents: 80% phenol or 50-88% trichloroacetic acid.
• Cryotherapy: Freeze with liquid nitrogen.

Warts (Verrucae): Common and benign cutaneous tumors due to infection of epidermal cells with human papillomavirus (HPV).

HPV Subtypes:

• Over 70 subtypes of DNA human papillomavirus (HPV) have been identified.
• Virus infects by direct inoculation through touch, sexual contact, or swimming baths.
• Specific clinical lesions associated with certain HPV subtypes, e.g. type 2 with common hand warts, types 1 and 4 with plantar warts, types 6, 11, 16, and 18 with genital warts.
• Genital HPV subtypes can cause cytological dysplasia of the cervix, which may be precancerous. Immunosuppressed individuals are particularly susceptible.

Common Warts

• Dome-shaped papules or nodules with a papilliferous surface. They are usually multiple and commonest on the hands or feet in children, but also affect the face and genitalia. Surface interrupts skin lines. Some facial warts are 'filiform' with fine digit-like projections.

Plane Warts

• Smooth flat-topped papules, often slightly brown in color, commonly found on the face and dorsal aspects of the hands. They are usually multiple and resist treatment, but eventually resolve spontaneously, often after becoming inflamed.

Plantar Warts

• Children and adolescents on the soles of the feet. Pressure causes them to grow into the dermis, resulting in painful warts covered by callus. Dark punctate spots (thrombosed capillaries) become visible when callus is pared. Several contiguous warts (HPV type 4) may fuse to form a large plaque, the so-called mosaic wart.

Genital Warts

• In Males: Affect the penis; in homosexuals, the perianal area.
• In Females: Affect the vulva, perineum, and vagina. Genital warts may be small or coalesce into large cauliflower-like growths known as ‘condylomata acuminata’.
• Transmission in Children: Genital warts in children may occur after inoculation during birth through an infected birth canal, as a consequence of sexual abuse, or from incidental spread from cutaneous warts.

Differential Diagnosis

• Molluscum Contagiosum: Infectious dome-shaped papules caused by a pox-virus, often with a central dimple containing whitish cheesy material.
• Calluses: Thickened areas of skin that develop due to friction or pressure.
• Condylomata Lata of Secondary Syphilis: Raised, wart-like growths seen in secondary syphilis.

Management

• Spontaneous Resolution: More than 50% of warts disappear within 2 years, but treatment is recommended to prevent spread to other sites.
• Keratotic Debris Removal: Gently pare excess keratotic debris with a scalpel until thrombosed capillaries are visible to enhance therapy response.
• Common Warts Treatment:
  • Destroy with liquid nitrogen or cantharidin application.
  • Light electrodesiccation and curettage can also be effective.
  • Daily application of 10–17% lactic acid and 10–17% salicylic acid in flexible collodion is a slow but painless removal method.
  • Recalcitrant warts may respond to 5% 5-fluorouracil ointment rubbed into lesions daily.
  • Avoid contact with adjacent normal skin to prevent irritation, erosion, or hyperpigmentation.
• Condylomata Treatment:
  • Weekly applications of 25% podophyllin in tincture of benzoin are effective.
  • Leave the medication on warts for 4–6 hours and then remove by bathing.