Chapter 054. Skin Manifestations of Internal Disease (Part 1)

Harrisons Internal Medicine Chapter 54. Skin Manifestations of Internal DiseaseSkin Manifestations of Internal Disease: IntroductionIt is now a generally accepted concept in medicine that the skin can show signs of internal disease. Therefore, in textbooks of medicine one finds a chapter describing in detail the major systemic disorders that can be identified by cutaneous signs. The underlying assumption of such a chapter is that the clinician has been able to identify the disorder in the patient and needs only to read about it in the textbook. In reality, concise differential diagnoses and the identification of these disorders are...
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Chapter 054. Skin Manifestations of Internal Disease (Part 1) Chapter 054. Skin Manifestations of Internal Disease (Part 1) Harrisons Internal Medicine > Chapter 54. Skin Manifestations ofInternal Disease Skin Manifestations of Internal Disease: Introduction It is now a generally accepted concept in medicine that the skin can showsigns of internal disease. Therefore, in textbooks of medicine one finds a chapterdescribing in detail the major systemic disorders that can be identified bycutaneous signs. The underlying assumption of such a chapter is that the clinicianhas been able to identify the disorder in the patient and needs only to read about itin the textbook. In reality, concise differential diagnoses and the identification ofthese disorders are actually difficult for the nondermatologist because he or she isnot well versed in the recognition of cutaneous lesions or their spectrum ofpresentations. Therefore, the authors of this chapter have decided to cover thisparticular topic of cutaneous medicine not by discussing individual disorders butby describing and discussing the various presenting clinical signs and symptomsthat indicate the presence of these disorders. Concise differential diagnoses will begenerated in which the significant diseases will be briefly discussed anddistinguished from the more common disorders that have no significance forinternal diseases. The latter disorders are reviewed in table form and always needto be excluded when considering the former. For a detailed description ofindividual diseases, the reader should consult a dermatologic text. Papulosquamous Skin Lesions (Table 54-1) When an eruption is characterized by elevated lesions, papules(1 cm), in association with scale, it is referred to as apapulosquamous lesion. The most common papulosquamous diseases—psoriasis,tinea, pityriasis rosea, and lichen planus—are primary cutaneous disorders (Chap.53). When psoriatic lesions are accompanied by arthritis, the possibility ofpsoriatic arthritis or Reiters disease should be considered. A history of oral ulcers,conjunctivitis, uveitis, and/or urethritis points to the latter diagnosis. Lithium, betablockers, HIV or streptococcal infections, and a rapid taper of systemicglucocorticoids are known to exacerbate psoriasis.Table 54-1 Selected Causes of Papulosquamous Skin Lesions1. Primary cutaneous disorders a. Psoriasisa b. Tineaa c. Pityriasis roseaa d. Lichen planusa e. Parapsoriasis f. Bowens disease (squamous cell carcinoma in situ)b2. Drugs3. Systemic diseases a. Lupus erythematosus c b. Cutaneous T cell lymphoma c. Secondary syphilis d. Reiters disease e. Sarcoidosisda Discussed in detail in Chap. 53.b Associated with chronic sun exposure and exposure to arsenic. c See also Red Lesions in Papulonodular Skin Lesions. d See also Red-Brown Lesions in Papulonodular Skin Lesions. Whenever the diagnosis of pityriasis rosea or lichen planus is made, it isimportant to review the patients medications because the eruption can be treatedby simply discontinuing the offending agent. Pityriasis rosea–like drug eruptionsare seen most commonly with beta blockers, angiotensin-converting enzyme(ACE) inhibitors, gold, and metronidazole, while the drugs that can produce alichenoid eruption include thiazides, antimalarials, gold, quinidine,phenothiazines, sulfonylureas, and ACE inhibitors. In some populations, there is ahigher prevalence of hepatitis C viral infection in patients with lichen planus.Lichen planus–like lesions are also observed in chronic graft-versus-host disease. In its early stages, cutaneous T cell lymphoma (CTCL) may be confusedwith eczema or psoriasis, but it often fails to respond to the appropriate therapy forthose inflammatory diseases. CTCL can develop within lesions of large-plaqueparapsoriasis and is suggested by an increase in the thickness of the lesions. Thediagnosis of CTCL is established by skin biopsy in which collections of atypical Tlymphocytes are found in the epidermis and dermis. As the disease progresses,cutaneous tumors and lymph node involvement may appear. In secondary syphilis there are scattered red-brown papules with thin scale.The eruption often involves the palms and soles and can resemble pityriasis rosea.Associated findings are helpful in making the diagnosis and include annularplaques on the face, nonscarring alopecia, condyloma lata (broad-based andmoist), and mucous patches as well as lymphadenopathy, malaise, fever,headache, and myalgias. The interval between the primary chancre and thesecondary stage is usually 4–8 weeks, and spontaneou ...