Warts and Its Types
Warts are tiny, rough, painless growths on the integuments. They represent miniature clusters of abnormal epithelial cells with surrounding dead cells, resembling either a solid blister or even a cauliflower.
Affecting 7 to 12% of the general population, these are mostly caused by Human Papilloma Virus (HPV). They can present in any part of the body, including the face and the genitals. [1, 2, 3]
This is an image of a wart, a cluster of abnormal epithelial cells.
Several types of warts exist: common (verruca vulgaris), flat (verruca plana), filiform, mosaic, plantar, and genital warts. They vary not only their shape, but also on their sites of preponderance, as well as the types of papilloma virus implicated. 
Also called verruca vulgaris, these warts appear like hard, elevated lumps with uneven exteriors. They range from 1mm to 1cm in size. They can appear anywhere, but are mostly located on the hands. Human Papilloma Virus 1, 2, and 3 are their usual suspects in etiology. [4, 5]
They are also coined as verruca plana or plane warts. These are smooth, non elevated, flesh colored lesions, with a diameter of 1 to 5 centimeters. Most common areas of predilection are the hands, shins, and the face. Brought about by Human Papilloma Virus 3, 10, 28 and 49, these lesions are often painless. [2, 6]
True to their word, these warts are usually located in the genitalia, particularly the vulva, penis and anus. Also called venereal warts, Verruca acuminata and Condyloma acuminatum, they appear as grayish lumps with a cauliflower shape. Transmission is frequently via sexual contact. [1, 4, 5]
These thread or finger like warts are also called digitate warts. They are usually skin –colored, and are located in the face, neck, lips and eyelids. Usually long and narrow, these are brought about by the human Papilloma Virus 1, 2, 4, 27 and 29. [2, 7]
Appearing as tightly clumped group of warts, each wart has an angular outline. They are usually present on distal parts of the upper and lower extremities.
These warts are presented as tiny, hard bumps with small dark dots. Usually found in the soles, they can usually be tender, causing difficulties on walking. [1, 5]
Warts on the Face
Facial warts, being the most visible, are some of the most common concerns for consultation to a dermatologist .Like the other types of warts, it is brought about by the Human Papilloma Virus. However, amongst the many types of warts, only two can be found on the face: the filiform and flat warts.
A patient with warts on his face.
Identifying Facial Warts
The warts located in the face are usually either colorless or skin-toned. They are generally characterized as elevated bumps, either single or in a series lined as a straight row, having a rough or smooth exterior, and averaging from 1 to 10 centimeters. [ 5, 8]As previously stated, facial warts can either be of filiform type, having an elongated, elevated, narrow and thread like development, or a flat type, with smooth and non elevated lumps. [2, 5]
These warts are usually associated with bleeding, pruritus, and may even be noticed to spread on other areas of the body. They are mostly painless, but can also become tender when located in areas predilected for friction. 
A flat wart found on a patient’s face.
A filiform wart on the face, near the eyelid.
Risk Factors in Acquiring Warts
Mainly brought by the Human Papilloma Virus, the following may serve as predisposing factors to one’s acquisition of warts:
- Prior episodes of skin injuries and trauma
- Infections of the skin
- Excessive sweating of the hands and feet
- Nail biting
- Swimming in public pools
- Direct contact with people infected with warts
- Shaving or scratching of other warts, contributing to its spread
- Using other people’s clothing
- Contact through objects
- Decreased immune systems [5, 7]
Facial Warts: Pathophysiology
More than a hundred strains of Human Papilloma virus are present. However, only a number are guilty of causing facial warts. Once exposed, the virus invades the epithelial layer of cells and then replicates in the upper layer of epidermis. Systemic propagation is virtually absent. Symptoms would usually be present 1 to 6 months after, but latency periods of as long as 3 years can also occur. 
A thorough physical examination is vital, but the complete past medical history can also provide clues to diagnosis. Appearance and duration or growth rate can also serve as basis of diagnosing the specific facial wart type. The diagnosis can be made based on clinical presentation.More advances methods for diagnosis include immunohistochemical detection, viral DNA identification by Southern blot hybridization, and Polymerase Chain reaction. When in doubt, a biopsy can also be done. 
Treatment Modalities for Facial Warts
Most facial warts resolve spontaneously. However, if removal of warts is desired, the following can be considered:
- If the facial warts are quite numerous or are large in size, keratolytic agents may be of help. Topical salicylic acid one of the most common keratolytic agents used, thus can be utilized for warts located in the face.
- A large, single wart can be removed with the use of either a cautery or by means of curettage
- If a wart is persistent, curettage and cautery may also be done for its removal
- Cryotherapy, with the use of nitrogen, can also be performed. In this method, the wart is frozen off and removed.
- This requires one to four sessions within one to two weeks.
- Application of Cantharidin can also cause drying up, blistering, and thus removal of the wart. This is similar to cryotherapy, but with a higher degree of temperature.
- Zinc supplementation is also found to reduce and eliminate warts. Consumed orally, it is given on a dose of 5 to 10mg/kg/day. Trials have also been done proving the efficacy of topically administered zinc, and zinc oxide.
- Laser therapy using either a carbon dioxide or a pulse dye laser can also be performed to remove these warts. These often take 2 to 4 treatment sessions, with 10 to 14 days interval.
- Similar to laser treatment, infrared coagulation may also be administered. This uses an infrared light like the laser, but is far less expensive.
- Home remedies can also be given. These include application of disinfectant, baking soda, aloe gel, dandelion saps, and even rub wood ash. [7, 10, 11, 12, 13]
Preventing Facial Warts
The following can be done to prevent occurrence of facial warts:
- Avoid contact with a patient with the human papilloma virus
- Refrain from sharing towels, and other clothing
- Have a strong immune system
- If the warts persist, consult a specialist 
- Shenefelt, P. Nongenital Warts. Medscape. 2011 June.
- Stefani, M, et al. Efficacy Comparison Between Cimetidine and Zinc Sulfate in the Treatment of Multiple and Recalcitrant Warts. An Bras Dermatology. 2009; 84(1):23-9
- Halasz, C, et al. Treatment of Common Warts Using the Infrared Coagulator. The Journal of Dermatologic Surgery and Oncology. 1994; 20 (4): 252-56.