Warts: Symptoms, Types, Causes and Treatment

Warts are one of those universal skin conditions that almost everyone encounters at some point in life. Though often harmless, they can be bothersome, persistent, or even emotionally distressing. Understanding warts—their symptoms, types, causes, and treatment options—can help both patients and caregivers make informed decisions and reduce the stigma or anxiety often associated with them. This comprehensive article brings together the latest clinical research and expert guidelines to provide a holistic, up-to-date guide on warts.

Symptoms of Warts

Warts may be small, but their impact on daily life can be far from insignificant. These benign skin growths, caused by the human papillomavirus (HPV), can appear on virtually any part of the body. Their symptoms range from cosmetic annoyance to localized pain and itching, depending on the type and location of the wart.

Symptom	Description	Frequency/Context	Source(s)
Raised lesion	Firm, rough-surfaced bump	Common in all types	1 2 5
Papillomatous	Wart with finger-like projections	Seen in filiform warts	5
Flat lesion	Slightly elevated, smooth, skin-colored	Common in plane warts	1 5
Pain	Localized discomfort or tenderness	Especially on soles (plantar warts)	1 6
Itching	Mild to moderate pruritus	Some patients	1
Bleeding spot	Pinpoint red/black dots	Seen in plantar and common warts	5
Cosmetic issue	Visible, unsightly appearance	Major concern for most patients	1

Table 1: Key Symptoms

Overview of Wart Symptoms

Warts have a diverse clinical appearance, but some characteristics are shared across most types.

Common Signs and How They Present

• Raised, Rough Lesion: Most warts are firm and have a rough, "verrucous" (warty) surface. They can range from a few millimeters to over a centimeter in size. Common warts often have a dome-shaped, cauliflower-like appearance 1 2 5.
• Papillomatous Growth: Some warts, especially filiform or digitate types, grow as elongated, finger-like projections, usually on the face or neck 5.
• Flat, Smooth Bumps: Plane warts (verruca plana) are flat-topped, skin-colored or slightly brownish, and usually appear in clusters on the face, hands, or shins 1 5.
• Pain and Discomfort: Plantar warts, which develop on the soles of the feet, often cause pain due to pressure from walking. Some people also report mild itching or tenderness 1 6.
• Bleeding or Black Dots: Small, pinpoint black or red dots (thrombosed capillaries) are often visible within the wart, especially in plantar and common types 5.
• Cosmetic Distress: While warts are medically benign, more than 90% of patients cite appearance as a primary concern, sometimes leading to social withdrawal or self-consciousness 1.

When to Seek Medical Attention

Most warts are harmless and may resolve spontaneously. However, consider seeing a healthcare professional if:

• The wart changes rapidly in size, color, or shape.
• There is significant pain, bleeding, or signs of infection.
• Warts appear in large numbers, spread quickly, or occur in people with weakened immune systems.
• The appearance is atypical or diagnosis is uncertain 1 2 6.

Types of Warts

Warts are not a one-size-fits-all condition. Their appearance and preferred body locations vary, influenced by the specific HPV type responsible for the infection. Knowing the different types can help in recognizing, diagnosing, and choosing appropriate treatments.

Type	Location(s)	Key Features	Source(s)
Common wart	Hands, fingers, knees	Rough, dome-shaped, firm	1 2 5 7
Plantar wart	Soles of feet	Painful, flat, callus-like	2 5 7
Mosaic wart	Soles, palms	Clustered, fused warts	1 8
Plane wart	Face, hands, shins	Flat, smooth, skin-colored	1 5 7
Filiform/digitate	Face, neck, eyelids	Thread-like, elongated	1 5
Genital wart	Genital, perianal	Soft, moist, cauliflower-like	1 2 4 7
Periungual	Around nails	Irregular, disrupt nail growth	3 7

Table 2: Types of Warts

Exploring Wart Varieties

Warts are classified by both their appearance and the area of the body they affect.

Common Wart (Verruca vulgaris)

• Most frequently seen on the hands and fingers.
• Firm, rough, dome-shaped nodules with a “cauliflower” texture.
• Often caused by HPV types 2, 4, 27, and 57 1 7 8.
• May appear singly or in clusters.

Plantar Wart

• Develop on the soles (plantar surface) of the feet.
• Flattened by pressure; may be painful when walking.
• Often have central black dots (thrombosed capillaries).
• Can occur as single lesions or in clusters (mosaic warts) 2 5 8.

Mosaic Wart

• A variant of plantar wart.
• Composed of tightly packed, fused warts forming a plaque.
• More common in females and often persistent 1 8.

Plane Wart (Verruca plana)

• Flat-topped, smooth, skin-colored or brownish papules.
• Common on the face, backs of hands, and shins.
• Typically caused by HPV types 3 and 10 1 5 7.

Filiform/Digitate Wart

• Finger-like projections.
• Usually found on the face, neck, or eyelids.
• More common in males 1 5.

Genital Wart (Condyloma acuminata)

• Occur on genital, perianal, and sometimes oral mucosa.
• Soft, moist, and often cauliflower-shaped.
• Associated with HPV types 6 and 11 (low risk) and 16, 18, 31, 35 (high risk) 2 4 7.

Periungual Wart

• Grow around or beneath fingernails and toenails.
• Can distort nail growth and are often difficult to treat 3 7.

Causes of Warts

Understanding the root causes of warts can help reduce their spread and guide prevention strategies. While the viral origin is well-known, many people are surprised by the number of different HPV types and the variety of factors that influence susceptibility.

Cause	Mechanism or Risk Factor	Key Points	Source(s)
HPV infection	Virus invades skin/mucosa	>150 types, each with preferred sites	2 6 7 8
Skin trauma	Entry via breaks in the skin	Microtrauma facilitates infection	6
Immunosuppression	Decreased immune response	Increases risk, persistence, complications	2 8
Communal exposure	Showers, pools, shared surfaces	Increases transmission risk	6
Occupational risk	Meat handlers, students	Higher incidence in certain professions	1 6
HPV type (genotype)	Different types, variable risk	Determines wart type and persistence	7 8

Table 3: Causes and Risk Factors

The Human Papillomavirus Connection

• HPV as the Causative Agent: Warts are caused exclusively by infection with the human papillomavirus (HPV), a DNA virus that infects the skin or mucous membranes 2 6 7.
• Diversity of HPV Types: Over 150 genotypes exist, but only a subset is responsible for cutaneous (skin) warts. For example, HPV types 1, 2, 4, 27, and 57 cause most common and plantar warts, while types 3 and 10 are responsible for plane warts 7 8.
• Virus Entry Points: The virus typically enters the skin through minor cuts, abrasions, or other disruptions of the epithelial barrier 6.

Risk Factors and Transmission

• Immunosuppression: People with weakened immune systems (due to illness or medications) are more susceptible, may develop more warts, and encounter persistent or difficult-to-treat lesions 2 8.
• Communal Environments: Using communal showers or walking barefoot in shared spaces (such as gymnasium floors or swimming pools) increases the risk of exposure 6.
• Occupational Hazards: Certain professions, such as meat handlers, students, and laborers, show higher incidence rates, possibly due to increased skin contact or microtrauma 1 6.
• Direct and Indirect Contact: Warts can be spread by direct skin-to-skin contact or indirectly via contaminated surfaces. Autoinoculation (spreading from one part of the body to another) is also common 2 6.

The Role of HPV Genotype

• Genotype Affects Severity and Persistence: Some HPV types are more likely to cause persistent or multiple warts, and a few are associated with higher risk of malignant transformation, especially in immunocompromised patients 2 7 8.
• Genital Warts and Cancer Risk: Certain high-risk HPV types (notably 16 and 18) are linked to malignancies, most notably cervical cancer, but also cancers of the anus, penis, and oropharynx 2.

Treatment of Warts

Wart treatment can be surprisingly complex. While some warts disappear on their own, others persist or recur, and no single therapy is universally effective. Treatment choices depend on wart type, location, patient preference, and available resources.

Treatment Type	Mechanism/Approach	Typical Effectiveness or Notes	Source(s)
Salicylic acid	Topical keratolysis	Best evidence, modest effect	10 13
Cryotherapy	Freezing with liquid N2	Similar to salicylic acid, more side effects	10 11 13
Immunotherapy	Stimulates immune response	Useful for resistant/multiple warts	3 11 12 14
Bleomycin	Intralesional cytotoxin	Uncertain benefit, possible side effects	10 13
Dinitrochlorobenzene	Contact sensitizer	May help refractory cases	10 13
Duct tape	Occlusive therapy	No proven benefit over placebo	10 13
Surgical removal	Excision/curettage	For resistant or problematic warts	6 13
Laser/photodynamic	Destruction of wart tissue	For recalcitrant or special cases	6 13
Vitamin D injection	Immunomodulatory effect	Promising for plantar warts	14

Table 4: Treatment Options

Evidence-Based Approaches

Treatments can be grouped into several categories. Each has pros and cons, and clinical evidence varies.

Topical Treatments

• Salicylic Acid: The most extensively studied and widely recommended topical therapy for common and plantar warts. Works by softening keratin and promoting gradual removal. Cure rates are modest but superior to placebo 10 13.
• Other Topicals: Agents like formaldehyde, glutaraldehyde, and silver nitrate have also been used, but data supporting their efficacy is limited 6 13.

Cryotherapy

• Liquid Nitrogen: Freezes and destroys wart tissue. Cryotherapy is roughly as effective as salicylic acid, though more aggressive freezing may be more effective but increases the risk of pain, blistering, and scarring 10 11 13.
• Frequency: No significant difference in cure rates at 2-, 3-, or 4-week intervals 10.

Immunotherapy

• Mechanism: Stimulates the body's immune system to target HPV-infected cells, addressing both treated and distant warts 3.
• Examples: Intralesional injections with purified protein derivative (PPD), vitamin D3, or antigens like Candida are promising, especially for multiple, resistant, or periungual warts 3 11 14.
• Efficacy: Immunotherapy and cryotherapy have shown similar efficacy, with immunotherapy sometimes offering better clearance for certain types and locations 11 12 14.

Other Modalities

• Bleomycin: Intralesional injections may be offered for recalcitrant warts but evidence is inconsistent, and side effects may include pain or nail loss 10 13.
• Contact Sensitizers: Dinitrochlorobenzene and similar agents may help refractory cases by inducing a local immune reaction 10 13.
• Duct Tape Occlusion: Once popular, but studies show no significant benefit over placebo 10 13.
• Surgical and Laser Treatments: Reserved for problematic warts due to risks of scarring and recurrence 6 13.
• Photodynamic Therapy: Can be helpful in select cases but is not standard 6 13.

Spontaneous Resolution and Prevention

• Natural Course: Many warts (up to 27% in placebo groups) resolve without treatment within months to a few years, especially in children and healthy adults 13.
• Prevention: Avoid direct contact with warts, use footwear in communal showers, and maintain good skin hygiene to minimize risk 6.

Conclusion

Warts are common, benign skin lesions caused by various strains of the human papillomavirus (HPV). While usually harmless, they can cause significant discomfort, cosmetic concern, and occasionally pain. There are multiple types, each with unique features and preferred body locations. Their development is influenced by HPV genotype, immune status, exposure, and minor trauma.

Treatment is often guided by wart type, patient preference, and available resources. The most evidence-based therapies are topical salicylic acid, cryotherapy, and immunotherapy, each with advantages and limitations. Many warts resolve on their own, but persistent, painful, or distressing cases benefit from medical intervention.

Key Points:

• Warts are caused by HPV, with more than 150 genotypes affecting humans 2 6 7.
• Presentation varies by type and location, from rough, raised nodules to flat, smooth papules 1 5 7.
• Risk factors include minor skin trauma, communal exposure, and immunosuppression 6 2 8.
• The most effective treatments are topical salicylic acid, cryotherapy, and immunotherapy; no single treatment is universally successful 10 11 12 13 14.
• Most warts in healthy people resolve spontaneously; prevention focuses on minimizing exposure and maintaining skin integrity 6 13.

Understanding warts—what causes them, how they appear, and the best ways to treat and prevent them—can turn an unwelcome nuisance into a manageable, often temporary, skin concern.