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Peutz–Jeghers syndrome

Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports Created by Dr. Edward Cowen from . Open full size image Peutz–Jeghers syndrome (PJS) is a rare autosomal dominant disorder characterized by gastrointestinal polyps, hamartomas, mucocutaneous pigmentation, recurrent abdominal pain from intussusceptions, and an increased risk of intestinal and…

Perioral dermatitis

Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports Open full size image Perioral dermatitis is a benign, acneiform, facial eruption of children and young female adults. It commonly affects the perioral area with small, inflammatory papules with or without an eczematous dermatitis with a classic zone of sparing…

Perforating dermatoses

Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports Open full size image The perforating dermatoses are a varied group of conditions characterized by the transepidermal elimination of dermal material. Four primary conditions are included in the discussion of the perforating disorders: Reactive perforating collagenosis (RPC), which is characterized…

Pemphigus

Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports Open full size image Pemphigus is a severe autoimmune blistering disease that affects the skin and mucosa and includes three main variants: pemphigus vulgaris; pemphigus foliaceus; and paraneoplastic pemphigus. It is caused by the production of autoantibodies directed against epidermal…

Pediculosis

Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports Open full size image Lice are wingless, dorsoventrally flattened, blood-sucking insects that are obligate ectoparasites of birds and mammals. Pediculosis denotes an infestation by Pediculus capitis (head louse), Pediculus humanus (body or clothing louse), or Phthirus pubis (pubic or crab…

Parvovirus infection

Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports Open full size image Infection with human parvovirus B19 (HPB19), a member of the Erythrovirus genus, causes a variety of well-described exanthems and can result in a spectrum of systemic illnesses. Erythema infectiosum, also known as fifth disease, is the…

Paronychia

Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports Open full size image Paronychia is characterized by inflammation of the proximal and/or lateral nailfolds, with the fingers being more commonly affected than the toes. Acute paronychia usually involves single digits, is a painful pyogenic infection that usually occurs after…

Parapsoriasis

Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports Open full size image The use of the description parapsoriasis or parapsoriasis en plaque , even as an umbrella term, remains controversial, and debate remains whether the variants described in this chapter are, in fact, precursors of cutaneous T-cell lymphoma…

Paracoccidioidomycosis

Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports Courtesy of Douglas Altchek, MD Open full size image Paracoccidioidomycosis (PCM) is a chronic, progressive granulomatous infection caused by the dimorphic fungus Paracoccidioides brasiliensis. It primarily affects the lungs after inhalation of the fungus that resides in soil and plants…

Papular urticaria

Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports Open full size image Papular urticaria is a common disease characterized by chronic or recurrent eruptions of 3- to 10-mm pruritic papules, wheals, vesicles, or bullae with central pallor caused by hypersensitivity to the bites of arthropods. Not all individuals…

Panniculitis

Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports Open full size image Panniculitis is a term describing the inflammatory diseases of subcutaneous fat. Embryologically, the subcutaneous fat derives from mesenchymal cells, which differentiate into adipocytes, or fat cells. A collection of adipocytes is termed a microlobule , and…

Palmoplantar pustulosis

Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports Open full size image Palmoplantar pustulosis (PPP) is an inflammatory skin disease characterized by chronic and relapsing pustular eruptions of palms and soles as the primary observed lesions. Although seen in combination with plaque psoriasis, gene expression microarray analysis suggests…

Palmoplantar keratoderma

Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports Open full size image Palmoplantar keratodermas (PPKs) consist of a heterogeneous group of disorders characterized by thickening of the skin of the palms and soles. The condition may be subdivided into primary, hereditary keratodermas, acquired forms, and conditions in which…

Orf

Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports Open full size image Orf (ecthyma contagiosum) is a zoonotic cutaneous infection caused by the orf virus of the genus Parapoxvirus . Transmission occurs due to direct exposure to infected animals and fomites. The most commonly associated animals are sheep,…

Oral lichen planus

Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports Open full size image Oral lichen planus (OLP) is a common chronic inflammatory disorder affecting all areas of the oral mucosa that rarely undergoes complete remission, even with treatment. Management Strategy All treatment should be aimed at eliminating erythematous and…

Onchocerciasis

Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports Open full size image Onchocerciasis is a major tropical parasitic infection caused by the filarial worm Onchocerca volvulus and is transmitted by blood-sucking Simulium spp. blackflies, which breed near fast-flowing rivers. The Global Burden of Disease Study 2017 estimated that…

Notalgia paresthetica

Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports Open full size image Notalgia paresthetica is a unilateral sensory neuropathy characterized by pruritus, tingling, burning pain, or hyperesthesia to light touch at the medial border of the scapula. Accompanying pigmentation or mild lichenification is secondary to scratching. Occasionally the…

Nevus sebaceus

Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports Open full size image Nevus sebaceus (NS), first described by Jadassohn in 1895, is a term for a congenital hamartoma of the epidermis and adnexal structures typically involving the scalp and face. It results from the mosaic expression of HRAS…

Nevoid basal cell carcinoma syndrome (Gorlin syndrome)

Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports Courtesy of Maral Kibarian Skelsey, Gary L. Peck Open full size image Gorlin (nevoid basal cell nevus, Gorlin–Goltz) syndrome (GS) is an autosomal dominant syndrome characterized dermatologically, especially by the development of large numbers of basal cell carcinomas (BCCs). The…

Neurofibromatosis, type 1

Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports Open full size image Type 1 neurofibromatosis (NF1), or von Recklinghausen disease, is an autosomal dominant multisystem disorder with highly variable expression. NF1 is caused by pathogenic variants of the neurofibromin gene ( NF1 ) on chromosome 17. The neurofibromin…