Diseases of the skin, hair and nails are a common reason for visits to family physicians and pediatricians.

Unfortunately, and for a variety of reasons, most physicians have limited training in dermatology throughout their medical school and residency years, thus it is no surprise that primary-care physicians are less proficient than dermatologists in diagnosing accurately many skin disorders. Considering approximately 6% of outpatient visits relate to skin problems and that non-dermatologists manage 60% of these patients, it is important for primary-care providers to be comfortable managing the more common dermatologic conditions.

The most common skin problems diagnosed by family physicians in one study included (in descending order): dermatitis, pyoderma, warts, tinea infections, epidermoid cysts, candida, acne and actinic keratoses; the same study found the top 10 and top 20 most common diagnoses accounted for 65% and 82% respectively, of all skin-related diagnoses.

Primary care physicians should be able to recognize and manage the 20 most common skin problems. In addition, it is imperative to recognize less common but serious skin conditions (e.g. melanoma, pemphigus), and refer them appropriately.

One technique essential to the management of many common skin lesions is liquid nitrogen cryotherapy. Cryotherapy is a popular treatment modality because it is relatively inexpensive, easy to use, does not require local anesthesia and has few complications. It is most commonly delivered as liquid nitrogen or nitrous oxide, and the spray canister approach is the preferred delivery route. The use of cryotherapy should be preceded by an understanding of which lesions are amenable to such therapy, the duration of treatment and the proper use of margins in therapy. This modality is effective in the treatment of actinic keratoses, seborrheic keratoses, solar lentigines, dermatofibromas, digital mucous cysts, keloids, molluscum contagiosum, condylomata and common warts.

A good knowledge of the different vehicles used in topical medications (e.g. ointments, creams, lotions, gels) is an important consideration in managing cutaneous problems. Topical corticosteroids represent a large component of the arsenal for managing skin problems. Their side-effects are a function of steroid potency, as is their cost (more potent steroids are generally more expensive). Primary-care physicians should be comfortable in prescribing most low- and medium-potency steroids, and may consider reserving more potent steroids for dermatologists.

The management of skin lesions in children differs from the approach used in adults. Physicians should avoid unnecessarily traumatizing or scarring children, so the use of invasive diagnostic techniques such as skin biopsies should be reserved for when they are essential to the management of the disease. Proper education of the parent and child, the use of distraction to allay fear and an appreciation of the maturity of the child when deciding on treatment are all beneficial in the management of skin problems in the pediatric population.

The first step in dealing with a patient presenting with a skin problem is the visual examination of the lesion. An appropriate history (see table, top of page) then augments the exam, and helps to establish the differential diagnosis and previous responses to treatment. As well, being able to describe lesions in an organized manner and using the proper terminology will improve diagnostic acumen, management and necessary referrals.

The diagnosis and current management of some of the most common skin conditions observed in the family practice setting are presented here.

Moderately inflammatory acne on the cheeks of a 45-year-old woman.

Acne vulgaris
This is an inflammation or blockage of pilosebaceous units, most commonly on the face, but also affecting the shoulders, back and chest. It is usually more severe in males, and has a lower incidence in Asians and African-Americans. Although it most commonly affects adolescents, it can extend into, or even begin in, adulthood. It is important to be aware of the psychological impact of acne as it can lead to low self-esteem, depression and embarrassment. The classic features are open (black) or closed (white) comedones, inflammatory papules and pustules. Different manifestations include comedonal acne, papulopustular acne, nodulocystic acne and acne conglobata. Pitted, depressed or hypertrophic scarring may occur with severe acne (especially nodulocystic).

Multiple actinic keratoses on a man's scalp, age 65 years.

Actinic keratosis
These are small (less than 1cm), single or multiple, discrete, rough, scaly lesions. They occur on chronic sun-exposed and damaged skin, typically in the elderly. They are found primarily on the head and neck, as well as the dorsum of the hands and forearms. These lesions are considered pre-cancerous, with a small percentage developing into squamous cell carcinoma over 10 to 20 years.

Treatment: Most commonly with liquid nitrogen cryotherapy for isolated lesions. For more widespread lesions and/or for longer-term remission, topical imiquimod therapy (Aldara) or topical 5-fluorouracil (Efudex) should be considered. Other treatments include chemical peels, photodynamic therapy and topical retinoids.

Dermatofibroma on the arm of a 45-year-old male.

Dermatofibroma
A very common, small (less than 1cm), firm, raised nodule, which is a slow-growing, painless, benign tumour. A dermatofibroma is a skin-coloured/pink/brown nodule with occasional brown circumference that is typically solitary, more common in females and the middle-aged, and usually found on the extremities (especially legs). They are occasionally associated with a history of trauma, such as an insect bite, ruptured cyst or ingrown hair. Clinical diagnosis can be supported by the presence of a ‘Dimple/Fitzpatrick’s sign’ (lateral compression with finger and thumb produces a depression/dimple).

Treatment: Unnecessary due to benign nature of the lesion, but liquid nitrogen cryotherapy can be effective to flatten and reduce the colouration. Surgical excision is effective and definitive.

Hand, foot and mouth disease in a four-year-old boy.

Hand, foot & mouth disease
A self-limited (seven to 10 days) systemic infection typically due to a Coxsackie viral infection. Most commonly seen in young children, it is highly contagious and spreads by direct contact. A clinical diagnosis, it appears as multiple small grey vesicles with a red halo on the fingers and toes, and ulcerative oral lesions.

Often there is a low-grade fever, malaise and complaints of a sore mouth, although symptoms may be more severe in some.

Treatment: Symptomatic since it is quickly self-resolving.

Impetigo

Impetigo on the leg of a seven-year-old boy.

An infectious skin disease, spread by direct contact, and most common in children. It can be first degree or second degree, and there are three types: nonbullous impetigo, bullous impetigo and ecthyma. Most cases (in excess of 90%) are due to Staphylococcus aureus, although occasionally it may be due to group A beta-hemolytic Streptococcus (GABHS) or a combination of both. It presents as a weeping area of 1 cm to 3 cm rounded lesions which heal with honey-coloured crusts. Lesions typically last days to weeks and resolve promptly with proper treatment.

Treatment: Consider swabbing the lesion for culture and sensitivity. Treatment is preventive (check family members for impetigo), topical (Fucidic acid, Mupirocin) or, for more diffuse cases, systemic (depends on organism, although erythromycin or cephalexin are both good options for 10 days).

Intertrigo
A malodorous dermatitis of flexural regions often secondary to bacterial or yeast infections and most commonly affecting the axillae, inframammary, groin and intergluteal areas. Initially appears as pustules on an erythematous base, which become confluent. It is particularly common in diabetics and obese individuals. It should be differentiated from erythrasma (bacterial infection by corynebacterium) and inverse psoriasis. Management involves keeping the area clean, cool, dry and separated.

Treatment: Options include nystatin or imidazole creams twice daily, as well as topical mild steroids. Absorbent powders can be quite helpful. Patients should avoid tight and occlusive clothing.

Head lice
This is an infestation of the scalp by wingless insects spread by direct contact (shared items or head-to-head), occurring mainly in children. Infestation is not related to poor hygiene. Head lice are difficult to see, particularly as most patients have fewer than 10 lice, so the diagnosis is by clinical findings confirmed by finding nits or lice. It can be asymptomatic, although itching is in some cases intolerable and can result in secondary infection. Occipital or cervical lymphadenopathy may be suggestive of lice. The eggs/nits are 1 mm, oval, grey-white and firmly attached to the base of the hair. This differs from dandruff, where the scales are easily removed. Lice live from 40 to 50 days as they go through three lifecycle stages.

Prevention: Avoid contact with possible contaminated items (e.g. hats, combs). Bedding, clothing and head gear should be washed and heat-dried, and the environment vacuumed; lice can survive up to 48 hours off the head. Persons who have been in close contact should also be treated.

Treatment:
1) Permethrin 1% cream rinse (Nix, Kwellada-P): reduces reinfestations due to protective residua, but should repeat treatment in seven days. Apply for 10 minutes then wash off; consider using a nit comb.

2) Isopropyl myristate and Cyclomethicone (RESULTZ): dissolves the waxy exoskeleton of lice. Not insecticidal (great for parents seeking “natural products”). Apply for 10 minutes then wash off, and consider using a nit comb. Repeat in seven days.

3) Other: Pyrethrin (e.g., R&C Shampoo), Malathion, Petrolatum (occlusion).

Note: Resistance to all topical insecticidal agents has been reported.

Molluscum contagiosum

Molluscum on the thigh of a seven-year-old girl.

A self-limiting (lasting six to 12 months) viral infection of the skin caused by the pox virus, most commonly affecting children. It also affects sexually active adults presenting with lesions in the pubic region. These are 1 mm to 5 mm smooth, firm, white/pink umbilicated papules found anywhere on the skin; they may be single or typically multiple. Although itching, tenderness or pain are uncommon, roughly 10% of patients develop an eczematous dermatitis surrounding the lesions.

Treatment: Unnecessary since self-resolving, but often requested by parents. Includes liquid nitrogen cryotherapy, curettage, electrodessication, topical cantharidin and imiquimod.

Scabies

Scabies in the hand web space of a 28-year-old man.

A parasitic infection usually transmitted by direct contact. Older patients in nursing homes are more prone to infestation, as are young children and sexually active young adults. Patients present with an itchy, eczematous, papular rash, most commonly in the finger webs, flexor aspect of wrists, elbows, buttocks and genitalia, with sparing of the head and neck. With the initial infection, sensitization (and pruritus) take a few weeks to develop, but after a reinfestation pruritus develops within 24 hours. Because a clinical diagnosis can be difficult to make, a scabies infection should be in the differential in the setting of a persistent generalized pruritus. Pruritus is often intense, widespread and worse at night, thus interfering with sleep. Unfortunately for some patients, this condition has been misdiagnosed and mistreated as an eczema for long periods of time.

Treatment:
1. Permethrin 5% cream (e.g. Nix, Kwellada-P) has low toxicity and excellent results. Wash off after eight to 12 hours.

2. Seven per cent to 10% precipitated sulfur in petroleum jelly. Use for very young infants, pregnant and lactating women. Apply for three consecutive days, left on for 24 hours after application and washed off before the next application.

Treatment is effective in more than 90% of cases. Clothes and bedding must be laundered in hot water. Make sure to treat close personal and household contacts at the same time, often regardless of symptoms. Pruritus may persist for weeks after successful treatment (“post-scabietic itch”).

Skin tags

A 48-year-old woman with multiple skin tags on her neck..

Skin tags are common, soft, skin- or tan-coloured pedunculated polyps. They occur commonly in intertriginous sites and increase in size and number over time. They are more common in older people, females (especially during pregnancy), and in obese patients. Skin tags are typically asymptomatic, but they may become bothersome and tender after trauma or torsion. These lesions are completely benign and thus only require management if the patient is symptomatic or for cosmetic purposes.

Treatment: Snipping with scissors, electrodesiccation or liquid nitrogen cryotherapy.

Darker skin types require careful treatment due to risk of hyper- or hypo-pigmentation.

Tinea pedis (athlete’s foot)
A dermatophytic infection of the feet that appears as erythema with scaling and maceration. Usually asymptomatic, but may be itchy or uncommonly painful if infected. Often a chronic condition made worse by hot climate. The two most common types are the interdigital (“athlete’s foot”) which can be a source for cellulitis of the foot, and the hyperkeratotic or moccasin foot.

Treatment:
1) Topical: ketoconazole (Ketoderm), terbinafine (Lamisil), ciclopirox olamine (Loprox), miconazole or clotrimazole.

2) Systemic (if extensive or topical failure): terbinafine (Lamisil), itraconazole (Sporanox)

Prevention: Wear shower shoes in public facilities, wash feet regularly, don’t share shoes.

Tinea versicolor (or pityriasis versicolor)

Tinea versicolor on the upper back of a 28-year-old woman.

A chronic, asymptomatic scaly rash of different colours (white, orange-brown or dark brown) with round macules usually less than 1 cm which liberate scale when scratched. It is caused by an infection by the Malassezia yeast. It is more common in young adults and most commonly appears on the upper trunk. Clinical suspicion along with a positive potassium hydroxide preparation make the diagnosis. It does not accentuate on Wood’s lamp, thus differentiating it from vitiligo.

Treatment: Options include selenium sulfide (2.5%) lotion or shampoo applied daily for 15 minutes for one week. Can also be treated with topical imidazoles (e.g., ketoconazole) for two weeks. Widespread or resistant lesions can be treated with oral itraconazole (100 mg twice daily for one week) or ketoconazole (400 mg single dose).

Patients should be reminded that this condition can recur and that prophylactic therapy with antifungal shampoos (e.g. Stieprox, Nizoral) or shampoos containing selenium sulfide (Selsun) or zinc pyrithione (e.g., Head & Shoulders) can prevent recurrence.

Warts/verruca
Common warts/Verruca vulgaris: This is a human papilloma virus infection of the epidermis that is transmitted directly through broken skin. Common warts are found typically on the fingers, palm and dorsum of the hand. They appear as firm, rough, skin or brown-coloured papules with tiny black dots on the surface. Treatment is only necessary if the warts are bothersome or for cosmetic purposes. In fact, most warts disappear spontaneously after an average of two years.

Treatment: The mainstay is cryotherapy, which is typically repeated on several occasions. Daily treatment with over-the-counter wart removal preparations (salicylic acid, lactic acid) are helpful but slower. Other treatment options include topical imiquimod or 5-fluorouracil, excision, laser ablation, intralesional bleomycin or candida therapy, and immunotherapy.

Plantar warts/Verruca plantaris: These warts appear as discrete, round papules with a rough surface, surrounded by a layer of hyperkeratosis. Although they are less a cosmetic issue, these are more likely to be treated because the hyperkeratosis around the wart may cause pain when walking.

Treatment: May consist of paring down the hyperkeratosis with a scalpel or pumice stone, which may relieve the pain, and use of over-the-counter salicylic acid preparations. If these don’t work, multiple courses of liquid nitrogen cryotherapy are often employed. Other treatment options include topical imiquimod or 5-fluorouracil, excision, laser ablation, intralesional bleomycin or candida therapy, and immunotherapy.

Dr. Benjamin Barankin, FRCPC, is a dermatologist in Toronto.