Dermatologists diagnose and treat diseases of the skin, hair, nails, and mucous membranes. That scope is broader than most people expect. Beyond acne and rashes, these specialists perform surgeries, screen for cancer, manage autoimmune conditions, and offer cosmetic procedures. They also frequently spot signs of internal diseases that first show up on the skin.
Common Skin Conditions
The bulk of a dermatologist’s workload involves chronic and recurring skin conditions. Acne, eczema (atopic dermatitis), psoriasis, and rosacea are among the most frequent reasons people book an appointment. Contact dermatitis, which flares when your skin reacts to an irritant or allergen, is another routine visit. For persistent itching without an obvious cause, a dermatologist can investigate underlying triggers that a general practitioner might miss.
Some conditions are less well known but equally common. Hidradenitis suppurativa causes painful lumps under the skin, often in the armpits or groin. Hyperhidrosis is excessive sweating that doesn’t respond to standard antiperspirants. Vitiligo, a pigmentation disorder that causes patches of skin to lose color, and its opposite, hyperpigmentation from sun damage or hormonal changes, both fall within this specialty. Rosacea, frequently mistaken for acne, requires a different treatment approach that dermatologists are specifically trained to distinguish.
Skin Cancer Screening and Treatment
Skin cancer is the most serious condition dermatologists manage on a regular basis. The three main types are basal cell carcinoma, squamous cell carcinoma, and melanoma. Basal cell and squamous cell carcinomas form in the outer layers of skin and are the most common. Melanoma develops in the cells that produce skin pigment and is the most dangerous, though it’s also the least common of the three.
During a skin exam, the dermatologist checks moles, birthmarks, and pigmented areas for abnormalities in color, size, shape, or texture. If something looks suspicious, a biopsy is the next step: the doctor removes as much of the abnormal tissue as possible, and a pathologist examines it under a microscope to confirm or rule out cancer. Precancerous growths called actinic keratoses, which appear as rough, scaly patches from years of sun exposure, are also routinely treated before they progress.
Surgical Procedures
Dermatologists perform several types of surgery, most of them outpatient. Standard excisions remove moles, cysts, or small skin cancers. Biopsies, where a small sample of tissue is taken for analysis, are one of the most common in-office procedures.
For high-risk or complex skin cancers, particularly those on the face, ears, or hands where preserving healthy tissue matters most, dermatologists may use Mohs surgery. This technique involves cutting away cancer one thin layer at a time and examining each layer under a microscope before removing the next. The process continues until no cancer cells remain. It’s done under local anesthesia, typically in an office or outpatient center. Most procedures take under four hours, though patients are usually told to set aside the full day since the extent of a cancer isn’t always visible on the surface. Mohs surgery has a high cure rate because the surgeon verifies clear margins in real time rather than estimating how much tissue to remove.
Hair Loss and Scalp Conditions
Dermatologists treat the full range of hair loss, from hereditary pattern baldness to autoimmune conditions like alopecia areata, where the immune system attacks hair follicles. For patchy alopecia areata, one treatment approach involves injections directly into the affected area. In one study of 127 patients, more than 80% who received these injections had at least half their hair regrow within 12 weeks.
Pattern baldness in both men and women can be managed with topical treatments like minoxidil, sometimes combined with microneedling to improve absorption. When thinning is advanced, a dermatologist may discuss hair transplant options. Scalp psoriasis, seborrheic dermatitis (the adult version of cradle cap), and a condition called acne keloidalis nuchae, which causes firm bumps on the back of the neck and is often mistaken for razor bumps, are also within their scope.
Nail Disorders
Nails are part of the skin system, so dermatologists handle conditions like fungal nail infections, ingrown nails, and nail psoriasis. Changes in nail color, texture, or shape can sometimes signal health issues elsewhere in the body. A nail that develops a dark streak, for instance, warrants evaluation to rule out melanoma under the nail bed.
Pediatric Skin Conditions
Children develop skin conditions that often look and behave differently than the same conditions in adults. Diaper rash is the most common skin issue in babies. Cradle cap, a form of seborrheic dermatitis, causes flaky patches on an infant’s scalp and is typically harmless. Baby eczema tends to appear on the face before spreading to other areas and can be more persistent than parents expect.
Some dermatologists complete additional fellowship training in pediatric dermatology, making them specialists in managing birthmarks, hemangiomas, genetic skin conditions, and severe eczema in infants and children. This subspecialty is formally recognized by the American Board of Dermatology.
Cosmetic Procedures
Cosmetic dermatology overlaps with medical dermatology more than people realize. Lasers used to reduce wrinkles can also treat vascular birthmarks, surgical scars, and sun damage. Microneedling, which creates tiny controlled injuries to stimulate collagen production and improve skin texture, is used both cosmetically and for scar treatment.
The most popular cosmetic treatment is botulinum toxin injections, commonly known as Botox, which temporarily relaxes muscles that cause wrinkles. Results typically last three to four months. Dermal fillers, which restore volume to areas like the cheeks or lips, can last one to two years depending on the product. Other options include chemical peels, radiofrequency microneedling (which adds heat to accelerate collagen production), and platelet-rich plasma therapy, where components of your own blood are applied to the skin after microneedling.
Most cosmetic procedures are out-of-pocket expenses. Insurance sometimes covers laser treatments for symptomatic vascular birthmarks or hemangiomas that are bleeding, painful, or ulcerated, and certain scar treatments may qualify for coverage as well.
Skin Signs of Internal Disease
Your skin can act as an early warning system for problems happening deeper in the body, and dermatologists are trained to recognize these signals. Lupus often produces a distinctive butterfly-shaped rash across the cheeks and nose. Dermatomyositis, an inflammatory muscle disease, can cause a violet-colored rash on the eyelids. Diabetes may show up as slow-healing wounds, darkened skin patches, or diabetic foot ulcers. Thyroid disorders can trigger hair loss, dry skin, or a waxy thickening on the shins.
Inflammatory bowel diseases like Crohn’s disease sometimes produce skin lesions, including painful ulcers or mouth sores, before gastrointestinal symptoms become obvious. Conditions like sarcoidosis, vasculitis, and certain lymphomas also have characteristic skin findings. A dermatologist who spots these patterns will typically coordinate with other specialists to get the right diagnosis.
Training and Subspecialties
Becoming a dermatologist requires four years of undergraduate education, four years of medical school, one year of broad clinical training in a field like internal medicine or surgery, and then a three-year dermatology residency. Dermatology residencies are among the most competitive in medicine.
After residency, dermatologists can pursue board certification through the American Board of Dermatology. Three recognized subspecialties offer additional certification: pediatric dermatology, dermatopathology (examining skin tissue samples under a microscope to diagnose disease), and micrographic dermatologic surgery, which covers Mohs surgery and the reconstructive procedures that follow cancer removal.