More common in Asian children than Caucasian children
Mongolian spots are congenital gray blue macular lesions, characteristically located on the lumbosacral area, although they can occur anywhere on the skin. They are almost always (99–100%) in infants of Asiatic or Amerindian origin, although reports in Black, and rarely, White infants have occurred. They usually disappear in early childhood, and generally the lesions are solitary.
May develop in long-standing scars
Squamous cell carcinoma of the skin can arise in areas of inflammation such as burn scars, chronic ulcers, radiation dermatitis, and chronic cutaneous lupus erythematosis. Other early lesions include solar keratoses, cutaneous horns, arsenical keratoses, and Bowen’s disease.
A 60-year-old man presents with the skin lesion pictured in Fig. Which of the following is the most likely diagnosis?
Bullous pemphigoid is most common in older adults. It is not as severe as pemphigus vulgaris, and histology reveals an absence of acantholysis, and immunofluorescence reveals specific antibodies in the basement membrane area.
An 18-year-old woman has severe acne for many years. She has tried many topical therapies with no lasting benefit. On examination, she has multiple inflammatory papules on her face, with some even larger nodules and cysts. Which of the following is the most appropriate next step in management?
Tetracyclines are commonly used in the treatment of moderate acne, but may be associated with risk of dental discoloration or photosensitivity. Isotretinoin is the most effective drug for severe acne, but is teratogenic, and may cause lipid abnormalities, hepatoxicity, and night blindness. It cannot be combined with tetracycline because of the risk of pseudotumor cerebri.
A 70-year-old man comes to the emergency department because of a skin rash and severe itching. He appears ill; there is a generalized skin rash that is scaly, erythematous, and thickened. His palms, soles, and scalp are also involved. Which of the following is the most likely diagnosis?
Exfoliative dermatitis is a rare skin condition, but because of its severity, patients with this syndrome are often admitted to a hospital. The syndrome can be primary, appearing in otherwise healthy individuals, or secondary to malignancy, contact dermatitis, drugs, or other dermatologic diseases (e.g., psoriasis). Even mild cases require systemic treatment for the severe itching. Antihistamines are usually the first choice
A 32-year-old woman comes to the emergency department because of a generalized erythematous skin rash. She was recently started on trimethoprim-sulfamethoxazole (Septra) for a urinary tract infection. Examination shows the diffuse rash involving her whole body including the palms and soles. Except for generalized lymphadenopathy, the rest of the examination is normal. Which of the following is the most appropriate interpretation of the generalized lymphadenopathy finding?
Most cases of exfoliative dermatitis will have widespread lymphadenopathy, whether they are primary or secondary forms. Biopsy will usually reveal nonspecific changes and is only warranted if there is a suspicion of lymphoma.
A 62-year-old man develops scaling and nonscaling patches, and plaques over his chest and back. They are itchy, but not painful. The rest of the examination is normal, except for lymphadenopathy. Examinations of the blood film and skin biopsy histology, both, reveal unusually large monocytoid cells. Which of the following is the most likely diagnosis?
These large cells are typical of Sézary syndrome, a leukemic form of cutaneus T-cell lymphoma (CTCL). This is frequently an early presentation of mycosis fungoides or CTCL. There may be a relationship to human T-cell lymphotropic virus (HTLV) I and II, but it is not universal. CTCL is a malignancy of helper T cells (CD 4+ ).
Which of the following statements about the prognosis of cutaneous T-cell lymphoma is true?
The typical course of mycosis fungoides is an initial erythematous stage (which might become diffuse and cause an exfoliative dermatitis as in this case), a plaque stage, and a tumor stage. The course is usually progressive through these stages, but all stages can be bypassed. The early stages may progress slowly with remissions or exacerbations. The disease can be rapidly progressive, particularly
Which of the following treatments is used for most patients with cutaneous T-cell lymphoma?
There is no curative therapy, and most experts provide treatment only when symptoms occur. Therapy includes topical treatments such as tar cream plus ultraviolet light or local nitrogen mustard, and systemic treatment with steroids and radiation therapy. Chemotherapy regimens are used but not with great success.
A 72-year-old man is newly diagnosed with bullous pemphigoid. Which of the following is the most appropriate next step in the management?
Severe cases require systemic steroids, often with the addition of azathioprine. Dapsone is useful in mild cases, and occasionally in very mild cases (or for local recurrences) topical glucocorticoid therapy will suffice
Which of the following features indicates a more negative prognosis for patients with malignant melanoma?
Nodular melanoma is invasive from the start. Women do better than men; trunk lesions and depigmented lesions carry a worse prognosis. Prognosis is directly related to depth of the lesion.
A 34-year-old man presents with a chronic and progressive skin rash. He has a history of poorly controlled Crohn’s disease and has lost 20 lb in the past 6 months. On examination, there are dry, scaly patches and plaques, which are sharply marginated and bright red around his mouth, and anogenital regions. There is also involvement of the flexural regions of the arms. Which of the following is the most likely diagnosis?
It is a persistent dermatitis around the mouth, with acral involvement that begins as vesicles but is soon crusted. Later it goes on to involve the scalp, hands and trunk, and feet. Treatment is zinc replacement in the diet. It has been described after prolonged parenteral alimentation, malabsorption states, intestinal bypass surgery, and chronic alcoholism. There is an inherited form (autosomal recessive) of the syndrome called acrodermatitis enteropathica. The inherited form occurs in infants and is also treated with zinc.
A 26-year-old woman develops discomfort on her lower legs and notices a skin rash. On examination, there are tender nodules on her shins with an erythematous base. Which of the following conditions is this rash associated with?
Erythema nodosum is a hypersensitivity vasculitis associated with many infections, drugs, malignancies, and inflammatory conditions (sarcoidosis). The peak age is 20–30 and it occurs more commonly in females. The lesions are rare in children. It is a nodular erythematous eruption, usually on the extensor aspects of the legs, less commonly on the thighs and forearms. It regresses by bruise-like color changes in 3–6 weeks without scarring.
Which of the following differentiates a patch from a macule?
A macule is a flat, colored lesion not raised above the surface of the surrounding skin. It is less than 1 cm in diameter. A patch differs from a macule only in size, being greater than 1 cm in diameter.
A 19-year-old man develops a rash in the groin area. On examination, it is a large welldemarcated area of tan-brown discoloration around his left inguinal area. There is some scaling of the lesion when brushed with a tongue depressor. Which of the following is the most appropriate initial diagnostic test?
A KOH preparation is useful when performed on scaling skin lesions, when a fungal etiology is suspected. The scraped scales are placed on a microscope slide, treated with one or two drops of KOH solution, and examined for hyphae, pseudohyphae, or budding yeast. A Tzanck smear is a cytologic technique for the diagnosis of herpes virus infection from vesicles, and diascopy is to assess whether a skin lesion will blanch with pressure.
A 7-year-old boy develops a skin rash in the right axillary area. On examination, there are superficial small pustules, with some that have ruptured and formed golden-yellow crusts. The area is itchy, but not painful, and he has no systemic symptoms. Treatment with oral antibiotics is started. Which of the following statements about this condition is most likely correct?
Impetigo is a superficial bacterial infection of skin caused by group A beta-hemolytic streptococci or Staphylococcus aureus. It is characterized by superficial pustules that rupture, resulting in a honey-colored crust. The bullous variant is more likely staphylococcal in origin. Treatment requires improving hygiene and soaking the crust, as well as oral antibiotics
A 20-year-old man who recently emigrated from Southeast Asia has chronic skin lesions on his back and chest. On examination, there are multiple well-defined hypopigmented macules with raised edges. They vary in size from 1.0 to 5.0 cm, and some have lost sensation to touch and pinprick.
Localized areas of vitiligo can be seen in numerous primary skin disorders. It can also be caused by systemic disorders such as sarcoidosis and tuberculoid leprosy. In the latter disorder, there is associated anesthesia, anhidrosis, and alopecia of the lesions. Biopsy of the palpable border will reveal granulomas.
A 47-year-old woman has symptoms of heartburn and skin changes in her hands. She notices pain and discomfort in her hands while washing dishes with cold water, and that the fingers sometimes become pale and colorless when they are painful. The fingers then change color to blue, and red after warming. On examination, there are areas of telangiectasias on her face.
Scleroderma is characterized by typical fibrotic and vascular lesions. These lesions may be periungual telangiectasias that are found in lupus erythematosus and dermatomyositis. Another form of telangiectasia, mat telangiectasia, is seen only in scleroderma. These lesions are broad macules 2–7 mm in diameter. They are found on the face, oral mucosa, and hands. The nail beds of scleroderma patients often reveal loss of capillary loops, with dilatation of the remaining loops when examined under magnification.
A 25-year-old woman presents with a diffuse skin rash, starting a few days after starting antibiotics for a urinary tract infection. On examination, her skin was warm to touch, and red in color.
Drug reactions most frequently result in papulosquamous reactions or diffuse erythroderma. Sulfa drugs frequently cause erythroderma. Other drugs commonly implicated include penicillins, gold, allopurinol, captopril, phenytoin, and carbamazepine. Fever, eosinophilia, and interstitial nephritis frequently accompany the erythroderma.
A 32-year-old man notices the sudden eruption of tiny nodules on his lower arms and knees. On examination, he has multiple crops of papules on his lower arms and knees. They are dome shaped, discrete, and have a yellow center with surrounding areas of redness.
Hyperlipoproteinemia is frequently associated with xanthomas, yellow-colored cutaneous papules or plaques. Xanthomas associated with hypertriglyceridemia are frequently eruptive; these yellow papules have an erythematous halo and are most frequently found on extensor surfaces of the extremities and buttocks.
A 24-year-old man presents with malaise, fever, and a new rash on his abdomen. Eight weeks ago he had a painless 1-cm ulcer on his penis that resolved spontaneously. On examination, there are faint pink brownish-red macules on his abdomen ranging in size from 0.5 to 1.0 cm.
The first exanthem of secondary syphilis is always macular and faint. Later eruptions may be papulosquamous and often involve the palms and soles. Associated findings that help make the diagnosis include annular plaques on the face, nonscarring alopecia, condylomata lata, mucous patches, lymphadenopathy, malaise, fever, headache, and myalgia.
A 51-year-old man with obesity (body mass index [BMI] >30) presents with skin changes in his right axilla. On examination, there is increased pigmentation and the skin appears dirty. The area feels velvety and the skin folds are accentuated.
Obesity is the most common cause of acanthosis nigricans—a velvety, localized hyperpigmentation. Other causes include gastrointestinal malignancy and endocrinopathy such as acromegaly, Cushing’s syndrome, Stein-Leventhal syndrome, or insulin-resistant diabetes.
Cancer chemotherapy most frequently involves rapidly proliferating elements of the skin, resulting in stomatitis and alopecia. Bleomycin, hydroxyurea, and 5-fluorouracil can cause dystrophic nail changes. Other skin manifestations of cancer drugs include sterile cellulitis, phlebitis, ulceration of pressure areas, urticaria, angioedema, and exfoliative dermatitis. The underlying malignancy often makes diagnosis of skin disease more difficult.
Chloroquine is used for certain skin diseases such as lupus and polymorphous light eruption, but can also cause skin reactions and exacerbate porphyria cutanea tarda. Black pigmentation can involve the face, mucous membrane, and pretibial and subungual areas.
Birth control pills
Birth control pills, sulfonamides, and penicillins are common drugs that can cause erythema nodosum. This is a panniculitis characterized by tender, subcutaneous, erythematous nodules characteristically found on the anterior portion of the legs.
The only common skin reaction with tetracyclines is photosensitivity. However, the drug is contraindicated in children under 8 years of age because of the risk of discoloring permanent teeth.
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