Inflammatory papules, pustules, and open comedones.

Prominent facial erythema, telangiectasia, rhinophyma, and scattered papules. (Courtesy Dr. L. From)

Diffuse area of mild scaling and hair loss. Erythema and pyoderma are occasionally present.

Sharply demarcated, circular patch of hair loss on scalp. Look for “exclamation mark” hairs at the periphery.

Hyperkeratotic, erythematous, slightly elevated papules and patches with a rough surface on sun-exposed skin. (Courtesy Dr. S. Walsh)

Hyperkeratotic, erythematous, slightly elevated papules and patches with a rough surface on sun-exposed skin. (Courtesy Dr. C. Forrest)

A domed, regularly bordered, smooth, round, dark brown papule.

Round, firm, yellow/flesh coloured, mobile nodule; may observe a follicular punctum on the overlying epidermal surface.

Violaceous cutaneous nodules on the lower extremity. (Courtesy Dr. J. Murray)

Erythematous, skin-coloured, firm, dome-shaped nodule with central keratin-filled crater.

Tan/brown, uniformly flat macule with irregular borders. (Courtesy Dr. S. Walsh)

Well-demarcated, waxy, brownish-black or tan papules/plaques; warty and “stuck-on” appearance.

Erythematous scaling patches. May see with hyperpigmentation, swelling, and ulceration. (Courtesy of Dr. L. From)

Greasy yellow-white scales and underlying erythema.

Sharply demarcated, weeping and crusting papules and vesicles.

Excoriated, lichenified plaques with erythema, dryness, and crusting.

Hyperpigmentation due to atopic dermatitis (eczema).

Atopic Dermatitis affecting the hands of an adult. (Courtesy Dr. S. Walsh)

Circumscribed, raised, edematous, red plaques surrounded by faint white halo. (Courtesy Dr. S. Walsh)

Widespread necrosis with painful blistering and denuding of epidermis.

The macules and papules can have various appearances but tend to be monomorphic in a given patient. (Courtesy Dr. S. Walsh)

Macules/papules with concentric, light and dark erythematous rings. (Courtesy of Women’s College Hospital Slide Library, Toronto)

Tender, poorly demarcated, deep-seated nodules usually on lower extremities. (Courtesy Dr. M. Mian)

Vitiligo
Sharply marginated, white patches completely devoid of pigment due to an acquired loss of melanocytes.

Indurated erythematous nodule or plaque with a hyperkeratotic surface, scale/crust, and central ulceration.

A pigmented lesion with asymmetry, an irregular border, variegated colour, and diameter greater than 6 mm.

Note central ulceration. (Courtesy Dr. S. Walsh)

Skin-coloured papule or plaque with rolled, translucent/pearly border and telangiectasia.

Skin-coloured papule or plaque with rolled, translucent/pearly border and telangiectasia.

Onychomycosis
Distal onycholysis, nail pitting, and subungual hyperkeratosis.

Deep-seated, dusky-red macules and creamy-yellow pustules progress to hyperkeratotic/crusted papules. (Courtesy Dr. S. Walsh)

Well-demarcated, erythematous plaques with thick, yellowish scale and desquamation on sites of pressure arising on the plantar surface of feet. (Courtesy Dr. S. Walsh)

Dry, well-circumscribed, silvery scaling, erythematous papules and plaques. (Courtesy Dr. S. Walsh)

Dry, well-circumscribed, silvery scaling, erythematous papules and plaques. (Courtesy Dr. L. From)

Violaceous, flat-topped polygonal papules on the flexural surface of the wrists. (Courtesy Dr. S. Walsh)

Flaccid vesicles and bullae that easily rupture; erosions and crusts. (Courtesy Dr. S. Walsh)

Multiple tense serous and partially hemorrhagic bullae; post-inflammatory hyperpigmentation is present at sites of prior lesions. Note the presence of uninvolved skin between lesions. (Courtesy Dr. S. Walsh)