Previously diagnosed patients with psoriasis may be receiving other topical agents, including a variety of other more or less potent topical steroids, tar derivatives, topical vitamin A derivatives (tazarotene), topical vitamin D agents, emollients, and ultraviolet light For severe cases, patients may be receiving treatment with systemic immunomodulating agents, including methotrexate, cyclosporine, acitretin, and a variety of biologic modifiers that address specific targets in T-cell physiology Patients with pustular or erythrodermic flares of their psoriasis may warrant admission in order to better control their disease, using more intensive wet wrap therapies with topical steroids or initiation of systemic immunomodulating therapies Patients with extensive skin involvement and skin barrier dysfunction may be at risk for hypothermia, skin infection, bacteremia, and electrolyte abnormalities, and should be evaluated accordingly Older patients with psoriasis are also at higher risk for cardiovascular disease and lipid abnormalities such as hypertriglyceridemia and hypercholesterolemia Seborrheic Dermatitis Seborrheic dermatitis is an inflammatory skin disorder characterized by salmon-colored erythema and greasy scale concentrated on areas rich in sebum production, including the scalp, eyebrows, ears, perinasal areas, beard areas, and less commonly, the midchest, axillary, and inguinal areas ( Fig 70.6 ) Despite the intensity of the rash, pruritus is often mild or nonexistent FIGURE 70.6 Infantile seborrheic dermatitis or “cradle cap.” Seborrheic dermatitis condition is most commonly seen in infants, adolescents, and adults This is typically seen as an isolated phenomenon; however, it may occur as an overlap with psoriasis (so-called “sebopsoriasis”), atopic dermatitis, or may arise in association with immunocompromised states, such as HIV, or Parkinson disease Scalp scaling is typically not associated with alopecia, which helps to differentiate it from tinea capitis The scalp involvement often shows a faint, fine scaling in contrast to the more localized, thickly crusted cornflake-like scale encountered in Langerhans cell histiocytosis (LCH) An inflammatory reaction to local infection with Malassezia species has been demonstrated and may explain the efficacy of antifungal treatment of seborrheic dermatitis In cases where systemic findings are associated with seborrhea that is new-onset, chronic, or particularly severe, workup should include evaluation for HIV, immune deficiency, or LCH Treatment depends on the sites of involvement For scalp involvement, an anti-inflammatory antifungal shampoo is appropriate: selenium sulfide, ketoconazole, or ciclopirox shampoos used daily for a week, and then maintained twice weekly is often sufficient The facial involvement can be managed with once- or twice-daily use of a topical anti-inflammatory antifungal creams such as clotrimazole or ketoconazole cream prn Occasionally, for more severe flares, brief courses of low-potency topical steroid (hydrocortisone 1% or 2.5%) or calcineurin inhibitor (pimecrolimus cream or tacrolimus ointment) can be applied twice daily for up to a week at a time on an as-needed basis As this tends to be a chronic, relapsing condition, advising appropriate follow-up is important Pityriasis rosea PR is a self-limited inflammatory skin disorder characterized by an initial larger herald patch or plaque, followed by the eruption of multiple smaller oval papules and plaques concentrated on the neck and torso areas Individual lesions often show a collarette of scale ( Fig 70.7 ) and typically follow lines of skin tension in a so-called “fir tree” or “Christmas tree” pattern The condition is most commonly seen among adolescents and adults Younger patients and those with darker skin may show atypical features with greater involvement of palms and soles, or an inverse pattern with concentrated areas in the intertriginous folds FIGURE 70.7 Pityriasis rosea with characteristic trailing edge scale within these oval papules and plaques PR is thought to be a reaction pattern to a preceding viral or other infectious process Reactivation of latent human herpesvirus or (HHV 6,7) has been postulated as one potential mechanism Given its clinical resemblance to secondary syphilis, adolescents and adults or those with risk factors for syphilis should be screened appropriately Chronic cases of what looks like PR lasting longer than the typical to weeks should be evaluated for pityriasis lichenoides Since the condition is self-limited and often asymptomatic, reassurance and anticipatory guidance may be sufficient For those who are symptomatic or desire a more rapid remission, treatment with oral acyclovir (ostensibly to treat HHV 6,7) or oral erythromycin (presumably for its anti-inflammatory properties) for 10 to 14 days may hasten resolution of the condition Pityriasis rubra pilaris PRP is a rare chronic inflammatory skin condition typified by salmoncolored, orange-red follicular papules and larger plaques accompanied by