It's never enjoyable to notice a strange new bump in your skin, and sometimes, it can be downright alarming. While most bumps, lumps, and swellings, people find in their skin are benign, some can require treatment, and some can even be cancerous. The MedlinePlus Medical Encyclopedia recommends you contact a medical professional in the event of "any unexplained lump or swelling."
According to the Dermatologic Disease Database, "Keratoacanthoma (KA) is a growth that is relatively common, benign, and most commonly found in elderly light-skinned individuals." Keratoacanthoma generally occurs on "the hands, arm, trunk, and face." A hard, red and skin-toned lump first grows rapidly, generally to a size of 1 to 3 cm over the course of a few weeks, then stops growing after six to eight weeks, remains the same size for two to six weeks, "and then finally spontaneously regress slowly" over the course of two to twelve months. Keratoacanthoma generally heals on its own with some scarring, but it can be treated with "surgical excision, electrodesiccation and curettage and multiple medical techniques."
According to MayoClinic.com, "folliculitis occurs when hair follicles become infected, often with Staphylococcus aureus or other types of bacteria." A folliculitis infection takes on the form of small, red, pus-filled pimples that form in clusters around hair follicles. Mild folliculitis causes red, inflamed skin, is uncomfortable and itchy and, if it's visible to others, can be unsightly and embarrassing. When a folliculitis infection is more severe, larger lumps appear and it can be painful and cause scarring and permanent hair loss. Severe infections require medical treatment, but superficial folliculitis can clear up on its own over a few days. If a folliculitis infection doesn't clear up on its own or becomes severe or recurrent, you should contact your doctor or dermatologist, who may recommend to treat it with antifungal medications or antibiotics.
Dermatofibromas, also known as histiocytomas, are common, tender, and noncancerous. They're firm to hard and range in color from skin colored to reddish. According to SkinSight.com, "these lesions usually persist for life, and they may heal as depressed scars after several years." Dermatofibromas generally pose no threat, but when found in large numbers in clusters they can occasionally be associated with immune problems like HIV, lupus or leukemia. Generally, no treatment is necessary, but you should see a doctor "if a lesion begins to increase in size, becomes painful or if large numbers of dermatofibromas in grouped or linear clusters are seen." When dermatofibromas are cosmetically undesirable or painful, steroid injections or liquid nitrogen freezing therapy can often reduce them in size. They can be surgically removed, but they often recur, so steroid injections or topical steroids are generally used after an excision to prevent recurrence.
According to MayoClinic.com, "Epidermoid cysts are small bumps that develop just beneath the skin on your face, neck, trunk and sometimes your genital area." These slow-growing, generally painless lumps are ordinarily hard and skin toned, but when they become infected, they turn red and become tender. Epidermoid cysts are almost always noncancerous, even though they can give rise to skin cancers; if they rupture, become infected or inflamed or are cosmetically undesirable, they can be surgically removed. Corticosteroid injections can reduce inflation in non-infected epidermoid cysts, and lasers and incision methods can be used to remove or eliminate them.
Keratosis pilaris is a common skin condition accompanied by small red or white bumps that generally don't itch or hurt and rough patches of skin that generally occur on the thighs, arms, and buttocks. According to MayoClinic.com, it "can be frustrating because it's difficult to treat," but it "isn't serious and doesn't have long-term health implications", and it "usually dissapears by age 30." Using a skin medication, such as a topical exfoliant, corticosteroid, or retinoid, may improve the appearance of the skin, but these creams have to be used continuously or symptoms will recur. Unfortunately, keratosis pilaris can persist for years.