Pityriasis Rosea • Pityriasis Rotunda • Granular Parakeratosis SMALL PLAQUE PARAPSORIASIS

Papulo-Squamous Disorders Papulo-Squamous Disorders • Small Plaque Parapsoriasis • Large Plaque Parapsoriasis • Pityriasis Lichenoides Et Varioliformis Acuta & Pityriasis Lichenoides Chronica • Pityriasis Rubra Pilaris • Pityriasis Rosea • Pityriasis Rotunda • Granular Parakeratosis SMALL PLAQUE PARAPSORIASIS

• Chronic, asymptomatic, erythematous scaly patches. Lesions are generally <5 cm in diameter or digitate.

• Histologically, mild, nonspecific spongiotic dermatitis with parakeratosis is seen

• CD4+ T cells predominance in the lymphocytic infiltrate

• A dominant T-cell clonality is demonstrable in some cases. • This group is significant for the tendency of its disorders to coexist or overlap with one another and for its association with lymphomas. • Small plaque parapsoriasis typically presents as round–oval patches that are generally <5 cm in diameter. • They are variably erythematous (but often less intense than psoriasis) and covered with a fine scale. • Variants: • Xanthoerythrodermia perstans: yellow hue • Digitate dermatosis: – Elongated – Finger-like patches – Symmetrically distributed – On the flanks. LARGE PLAQUE PARAPSORIASIS

• Chronic, asymptomatic, erythematous scaly patches • Lesions are generally >5 cm in diameter • Histologically, a nonspecific spongiotic dermatitis or an interface lymphocytic infiltrate with a variable degree of lichenoid features is seen • CD4+ T cells predominance in the lymphocytic infiltrate • A dominant T-cell clonality is demonstrable in many cases • It is thought that large plaque parapsoriasis represents the earliest stage of mycosis fungoides • Variably erythematous, round or irregularly shaped, scaly patches that are >5 cm in diameter. • They may or may not exhibit the clinical triad of atrophy, telangiectasia, and hyper/hypopigmentation (poikiloderma vasculare atrophicans). • Variant: “Retiform parapsoriasis” • Syn. Parapsoriasis variegata, parakeratosis variegata or parapsoriasis lichenoides. • Rare variant. • Widespread, ill-defined patches in a net-like or zebra-stripe pattern. • It progress to overt MF.

PLEVA & PLC

• Pityriasis Lichenoides Et Varioliformis Acuta & Pityriasis Lichenoides Chronica

• Mucha–Habermann disease (PLEVA)

• Guttate Parapsoriasis (PLC) • PLEVA & PLC are two ends of a disease spectrum. • Both entities are characterized by: – Recurrent crops of spontaneously regressing erythematous papules. – PLEVA: Crusted and occasionally vesiculopustular. – PLC they are scaly. • Individual patients may show intermediate or mixed lesions. PLEVA: A, B, C PLC: D Overlap: E Overlap

PI Hypopigmentation

PITYRIASIS RUBRA PILARIS (PRP)

• Follicular papules with an erythematous base are a characteristic finding, including on the proximal dorsal fingers. • Coalescence of orange–red plaques, but with obvious islands of sparing. • ±An orange–red waxy palmoplantar keratoderma. • Six types described, the classic adult form is the most common. • The classic types (adult and juvenile) typically resolve within 3–5 years.

Treatment of PRP

• Oral Vitamin A: – Successful treatment – Sometimes in combination with vitamins B and D. • Systemic retinoids: – Isotretinoin: 1–1.5 mg/kg/day (3-6 ms) – Acitretin – Alitretinoin – Effect of retinoids on familial PRP appears less certain.

• Methotrexate: – Significant clinical improvement of PRP. – Weekly oral or SC doses of 10–25 mg (3-6 ms). • Combinations (MTX+AcitrEtin): – In severe cases – MTX: (5–30 mg/week) plus Acitretin. – Simultaneously or add after inadequate response. – Increased risk for hepatotoxicity. • Biologic: – Case reports & small case series. – TNF-α inhibitors (etanercept, infliximab, adalimumab), secukinumab and ustekinumab). • Other potential therapies: – Systemic immunosuppressives (e.g. azathioprine, prednisone, cyclosporine) – Success with narrowband UVB, UVA1, or PUVA in combination with an oral retinoid – ?? one patient with UVB-provoked PRP. PITYRIASIS ROSEA

• A self-limited papulosquamous eruption that is occasionally pruritic. • Primarily in adolescents and young adults, favoring the trunk and proximal extremities. • Herald patch followed by lesions that are usually oval in shape and oriented with their long axes along Langer cleavage lines • Less common variants include inverse, vesicular, purpuric, and pustular

Differential Diagnosis

• 2ry Syphilis. • Drug eruptions: that can mimic pityriasis rosea; (ACE inhibitors, β-blockers, Metronidazole, and isotretinoin, Arsenic, Bismuth, Gold, Barbiturates, Clonidine, Hydrochlorothiazide, Omeprazole, Terbinafine, TNF-α inhibitors, NSAIDs & multiple vaccines). • A drug-induced pityriasis rosea-like eruption is often slower to resolve. • The herald patch or generalized eruption: – Tinea corporis – Tinea versicolor – Nummular dermatitis. • Vesicular pityriasis rosea vs Guttate psoriasis • Papulosquamous disorders such as pityriasis lichenoides. Treatment • Asymptomatic and self-limited: – Patient education and reassurance. • Pruritus: – Counterirritant antipruritic lotions – Low- to medium-strength topical corticosteroids. • More severe cases: – UVB phototherapy (broadband or narrowband) – Natural sunlight exposure and oral antihistamines. – Rarely, a brief course of systemic corticosteroids. • In a double-blind, placebo-controlled trial, 73% of patients had complete resolution after receiving 14 days of erythromycin in divided doses. The placebo group showed no resolution over the same time. • In a bilateral comparison trial of UVB, a reduction in severity, but not pruritus or duration, was observed. • One non-randomized study reported that acyclovir (800 mg five times daily for 1 week) led to a faster resolution of lesions and fewer new lesions. PITYRIASIS ROTUNDA

• Asymptomatic dermatosis seen primarily in the Far East and Mediterranean basin and in individuals of African descent. • Large circular and polycyclic scaly patches with sharp margins and no evidence of inflammation clinically. • Mostly, lesions are hyperpigmented and localized to the trunk and extremities. • A hypopigmented halo in some patients, and sometimes the entire lesion is hypopigmented. • 2 groups: • Type I: – In blacks and Asians – Hyperpigmented, in association with an internal malignancy, no family history. • Type II: – In Caucasians – Numerous (>30) lesions; a family history no internal malignancy.

• Histologic features are similar to those of ichthyosis vulgaris, raising the possibility of an unusual form of ichthyosis. • In some patients it may be associated with malnutrition, mycobacterial infections, and/or underlying malignancies, while in others it is familial. Differential Diagnosis

• Tinea Corporis

• Tinea Versicolor

• Leprosy

• Large Plaque Parapsoriasis.

• Progressive Macular Hypomelanosis Treatment

• Relatively difficult to treat. • Trials with topical lactic acid, urea, tars, emollients, and corticosteroids have provided little benefit. • Topical Tretinoin cream 0.1% can result in modest improvement. • Systemic Retinoids: extensive disease • Reversal of any underlying disorder. GRANULAR PARAKERATOSIS

• Synonyms: – Axillary granular parakeratosis, Intertriginous granular Parakeratosis. • The primary lesions are pruritic brownish-red keratotic papules that can coalesce into plaques. • The adult form: occurs almost exclusively in women. • Localized to the axillae, but other intertriginous sites can be affected. • The infantile form: is associated with diaper wearing as bilateral plaques in the inguinal folds or erythematous geometric plaques underlying pressure points from the diaper. • Histopathologically, there is distinct retention of basophilic keratohyaline granules within areas of parakeratosis in the stratum corneum. • A defect in processing profilaggrin to filaggrin is a proposed mechanism.

Differential Diagnosis

• Common causes of intertrigo: – Seborrheic dermatitis – Candidiasis – Inverse psoriasis – Erythrasma – Hailey–Hailey disease, Darier disease, P. vegetans • Seborrheic keratoses • Acanthosis nigricans. • Irritant Allergic Contact Dermatitis. Treatment

• Based upon case reports and small series, therapeutic success has been reported: – Topical corticosteroids – Vitamin D analogues – Retinoids – Cryotherapy – Oral isotretinoin and oral antifungals • Spontaneous resolution has also been observed (including in infants), as have relapses.