Arms

Arms

OVERVIEW

The upper arms and forearms have two contrasting aspects—the sun-exposed extensor surface and the sun-protected flexor surface. Different conditions affect each side. Predictably, the sun-exposed extensor arm is subject to sun damage (dermatoheliosis), photo eruptions, actinic keratoses, squamous cell carcinomas, keratoacanthomas, solar lentigines, and melanoma.

The inner, sun-protected flexural areas of the arms and legs, the antecubital and popliteal fossae, common settings for atopic dermatitis, are discussed together here. The extensor elbows and knees are primary sites for psoriasis, and the extensor legs are frequently places for lichen planus and scabies to appear.

Figure 13-1 Keratosis pilaris.

The tiny papules, some with surrounding erythema, give a rough grater-like texture to the skin.

UPPER ARMS

Keratosis Pilaris

Distinguishing Features

Tiny, rough, red, or tan spiny follicular papules distributed in a grid-like pattern on the deltoid areas (Fig. 13-1)
“Goose flesh,” “sandpaper-like” texture when palpated

Follicular Eczema

Distinguishing Features

Characterized by the appearance of small, rough, erythematous papules in a grid-like pattern, often with crusting and marked pruritus

Figure 13-2 Follicular eczema.

Note the grid-like pattern of tiny (1 mm) follicular papules, a common presentation in African American patients who have atopic dermatitis.

Pityriasis Alba

Pityriasis alba is a common skin condition affecting children and adolescents aged 3 to 16 years. The hypopigmented spots are mostly seen on the face in children who have atopic dermatitis (see also Cheeks). As with follicular eczema, described above, pityriasis alba is most often noted in children of color.

Distinguishing Features

Asymptomatic
Lesions most often appear on the lateral upper arms (Fig. 13-3) as well as the cheeks (see Fig. 7-6)
Present as one or more round, oval, or irregular whitish patches or thin plaques, with or without fine surface scale
Often appears following sun exposure because tanning of surrounding skin unmasks affected areas
Resolves spontaneously

Figure 13-3 Pityriasis alba.

These whitish round patches most often appear on the cheeks (Fig. 7-6) and lateral upper arms in those with atopic dermatitis.

Figure 13-4 Acne vulgaris.

Small papules and pustules of acne are present in this teenager.

Acne Vulgaris

Distinguishing Features

Inflammatory acneiform lesions, papules, and pustules (Fig. 13-4)

ELBOWS

Localized Plaque Psoriasis

Localized plaque psoriasis on extensor joints, the elbows and knees (see also Fig. 18-9), is the most common presentation of psoriasis. Involvement may remain limited and localized or may become unstable and become widespread (see Trunk). The activation of T lymphocytes leads to release of cytokines and results in proliferation of keratinocytes.

Lesions of psoriasis result from this increase in epidermal cell turnover. The cell’s transit time from the basal layer of the epidermis to the stratum corneum is decreased from the normal 28 days to 3 or 4 days. This “turned-on” epidermis, with its rapid accumulation of cells, accounts for the characteristic lesions of psoriasis—red papules and plaques. It also explains the accumulation of white or silvery (micaceous) scale due to the great increase in cellular kinetics which prevents time enough for shedding.

Distinguishing Features

Lesions may vary from well-demarcated, whitish or silvery erythematous plaques on the elbows (Figs. 13-5 and 13-6) and knees
Plaques can be very thick and hyperkeratotic
Usually not pruritic
Generally symmetric in distribution

Figure 13-5 Localized plaque psoriasis.

Note the well-circumscribed erythematous plaques surmounted by a fine scale.

Figure 13-6 Localized plaque psoriasis.

Bilateral symmetry, and the silvery, shiny luster (micaceous scale) of psoriasis.

Diagnosis

Clinical

Management

If necessary, thick hyperkeratotic scale can be removed with a keratolytic agent such as Keralyt gel, Salex cream, urea-containing creams, or prescription retinoid treatments.

The use of a potent (class 1) topical steroid for a limited period, followed by a less-potent topical steroid for maintenance
Occlusion of topical steroids of a medium- or high-potency agent is applied and then covered with polyethylene wrap (e.g., Saran Wrap) for several hours or overnight. Alternatively, the application of Cordran Tape, an occlusive tape that is impregnated with the steroid flurandrenolide may be used. This is helpful for occlusive therapy when relatively small areas are treated
- Intralesional steroids (2.5 to 5 mg/mL) can be helpful for thicker plaques
- See Tables 13.1 and 13.2 for information on topical steroids and agents used to treat psoriasis

Maintenance

Less-potent topical steroids can be used for maintenance (e.g., triamcinolone 0.1% ointment) daily
Topical calcitriol ointment (Vectical)
Topical calcipotriene vitamin D₃ cream (Dovonex)
Topical vitamin D₃-potent steroid combination ointment (Taclonex)
If tolerated, natural sun exposure should be encouraged when available
Phototherapy

Helpful Hint

Rotational therapy: This strategy decreases cumulative side effects and drug tolerance (tachyphylaxis), and often allows for lower dosages and shorter durations of therapy for each agent. For example, the use of a superpotent (class 1) topical steroid, such as clobetasol, may be applied for 2 weeks, discontinued for 1 or 2 weeks, and then restarted. Alternatively, clobetasol may be used on weekends only and Vectical ointment can be used during the week

Table 13-1 Topical Steroids Used to Treat Psoriasis

Potency	Generic Name	Brand Name
Class I	Clobetasol propionate 0.05%, ointment, cream, gel, foam, lotion, solution	Temovate, Ultravate, Olux foam, Clobex lotion, Cormax scalp solution
	Halobetasol propionate 0.05% cream, lotion	Ultravate, Bryhali
	Flurandrenolide	Cordran Tape small or large roll
Class II	Desoximetasone 0.05% gel	Topicort
	Fluocinonide 0.05% cream/ointment/solution/gel	Lidex
Class III	Fluticasone 0.005% ointment	Cutivate
Class IV	Triamcinolone acetonide 0.1% ointment	Kenalog
	Betamethasone valerate 0.12% foam	Luxiq foam
	Hydrocortisone valerate 0.2% ointment	Westcort
Class V	Triamcinolone acetonide 0.1% cream	Kenalog
	Hydrocortisone valerate 0.2% cream	Westcort
Class VI	Desonide 0.05% ointment, cream, gel, lotion, foam	DesOwen
	Aclometasone 0.05% ointment and cream	Aclovate
Most preparations are available in tubes of 15, 30, or 60 g lotions, solutions, creams or ointments.

Table 13.2 Other Topical Agents Used to Treat Psoriasis

Generic Name	Brand Name
*Keratolytic agents*
Salicylic acid 6%	Keralyt gel (1 oz)
Salicylic acid 6%	Salex cream (400 g) and lotion (441 mL)
*Topical vitamin D3 analogs*
Calcipotriene 0.005% cream, solution, foam	Dovonex cream, scalp solution Sorilux foam
Calcitriol 0.003% ointment	Vectical ointment
Tacalcitol ointment, lotion	Curatoderm, Bonalfa
Topical vitamin D3-topical steroid combination
Calcipotriene 0.005% and betamethasone dipropionate 0.064% ointment, solution, foam	Taclonex ointment or scalp solution Enstilar foam
*Topical retinoids*
Tazarotene 0.05%, 0.1% cream, gel, lotion	Tazorac cream, gel
*Topical retinoid- topical steroid combination*
Halobetasol propionate 0.01% and tazarotene 0.045 %	Duobrii lotion
*Anthralin preparations*
Anthralin 0.1%, 0.25%, 0.5%	Drithocreme, Dritho-Scalp
Anthralin 1% cream	Psoriatec
*Tar preparations*	Estar,^a PsoriGel,^a Balnetar^a
Note: All tar preparations (except liquor carbonis detergens) must be used in grease- or oil-based vehicles. Tar is commonly available in shampoos and is often combined with salicylic acid. Liquor carbonis detergens is an alcohol-extracted tar.
^aAvailable over-the-counter.