Peer Reviewed


A Collection of Dermatologic Disorders

Confluent and Reticulated Papillomatosis


Thomas Brown, DO; Charee Howard, DO; and Barbara Farrell, DO
Broward Health Medical Center, Fort Lauderdale, Florida


Consultant. 2018;58(2):72-73. 


A 19-year-old black man of Haitian decent with no significant medical history presented with a rash that had been present for 5 years and had developed shortly after he had arrived in the United States from Haiti. The patient reported that the rash had started centrally on his neck and trunk and had progressively spread to his arms and legs bilaterally. He denied associated pruritus, erythema, bleeding, joint pain, or fever. The patient reported that heat and perspiration were aggravating factors, and he denied any alleviating factors.

History. The rash initially had been evaluated 4 years prior and had been diagnosed as tinea versicolor. The patient had been treated with oral fluconazole, 300 mg once weekly for 4 weeks, along with the daily application of topical selenium sulfide. The patient reported that the treatment had not resulted in any improvement.

Physical examination. The patient appeared healthy and groomed appropriately and was in no distress. Examination of the skin revealed thickened, hyperpigmented, violaceous brown papules coalescing into plaques on the trunk and the flexor surfaces of the arms and legs (Figure 1). Microscopic findings of a potassium hydroxide preparation test revealed no hyphae.




The patient received a clinical diagnosis of confluent and reticulated papillomatosis (CARP).

Discussion. CARP was first described more than 60 years ago by French dermatologists Gougerot and Carteaud.1-3 Cases have since been reported worldwide among all ethnicities and skin types.3 There is no sex predilection, and the mean age of onset is 15 years.3,4

While skin dermatoses typically present with pathognomonic clinical and histological features, CARP is an uncommon skin condition thought to be caused by disordered keratinization.1 It shares many similarities with more common skin conditions without any identifiable features of its own. Although CARP is uncommon, this patient’s case demonstrates its ability to masquerade as other skin disorders. Most often it is misdiagnosed as tinea versicolor or acanthosis nigricans.1-5

The condition is usually asymptomatic, although it occasionally may be associated with pruritus.3 It is limited to the skin, with no systemic manifestations. It is characterized by multiple subcentimeter, hypopigmented or hyperpigmented, hyperkeratotic or verrucous papules that coalesce to form a reticular pattern peripherally and confluent plaques centrally on the neck and upper trunk.1,2

There is no clear consensus on the etiology of CARP, although the current theory is that it is secondary to infection with the bacteria Dietzia papillomatosis.3 Skin manifestations that persist after antifungal treatment should raise the index of suspicion for CARP.1

Oral minocycline is the pharmacologic treatment of choice.1,2,4 Other treatment options include oral clarithromycin, erythromycin, or azithromycin.3

Outcome of the case. The patient was treated with minocycline, 50 mg twice daily for 6 weeks, which resulted in almost complete resolution of his eruption (Figure 2). 




  1. Hudacek KD, Haque MS, Hochberg AL, Cusack CA, Chung CL. An unusual variant of confluent and reticulated papillomatosis masquerading as tinea versicolor. Arch Dermatol. 2012;148(4):505-508.
  2. Jo S, Park HS, Cho S, Yoon H-S. Updated diagnosis criteria for confluent and reticulated papillomatosis: a case report. Ann Dermatol. 2014;26(3):​409-410.
  3. Lim JH-L, Tey HL, Chong W-S. Confluent and reticulated papillomatosis: diagnostic and treatment challenges. Clin Cosmet Investig Dermatol. 2016;​9:217-223.
  4. Davis MDP, Weenig RH, Camilleri MJ. Confluent and reticulate papillomatosis (Gougerot-Carteaud syndrome): a minocycline-responsive dermatosis without evidence for yeast in pathogenesis. A study of 39 patients and a proposal of diagnostic criteria. Br J Dermatol. 2006;154(2):287-293.
  5. Park YJ, Kang HY, Lee E-S, Kim YC. Differentiating confluent and reticulated papillomatosis from acanthosis nigricans [published online September 28, 2015]. J Cutan Pathol. doi:10.1111/cup.12581


NEXT: Pemphigus Vulgaris Flare Due to Sunburn

Pemphigus Vulgaris Flare Due to Sunburn


Eric C. Schmidgal, MD
San Diego, California

Consultant. 2018;58(2):73-74. 

A 46-year-old woman with a history of pemphigus vulgaris (PV) presented to an outpatient clinic with blistering on her bottom lip. She reported having gone to the beach the previous day, but reported having applied sunscreen. She had no recent history of trauma to her lip. She denied fever, chills, recent illness, or other rashes or lesions. She further denied a history of infection with herpes simplex virus 1 or having started any new medications.

On examination, she was afebrile with normal vital signs. The rest of the physical examination findings were unremarkable, apart from the lesions on her bottom lip.

The patient’s PV had been in remission for several years on low-dose systemic prednisone therapy. Given her medical history, the presence of ruptured bullous lesions typical of PV, and the tendency for PV to present on the oral mucosa, the patient received a diagnosis of a PV flare due to sun exposure on her unprotected lips.

Discussion. PV is an autoimmune, intraepidermal blistering disease of the skin. Acantholysis occurs at the suprabasilar level in PV, whereas in pemphigus foliaceus, a related disorder, acantholysis occurs at the subcorneal level. Prior to the widespread use of glucocorticoid therapy, both diseases were fatal. The target of the autoantibodies is desmoglein, a cell-to-cell adhesion molecule. When desmoglein molecules are damaged, the bond between neighboring keratinocytes is weakened, which affects the integrity of the epidermis.1 Known triggers of PV include emotional stress, infections, certain drugs, thermal burns, and UV radiation.

The authors of one case study demonstrated a potential mechanism for UV radiation contributing to the acantholysis that is characteristic of pemphigus.2 Biopsies taken from sites of pemphigus foliaceus were exposed to UV radiation and studied histologically and with immunohistochemistry techniques. Both methods enhanced binding of antibodies to the epidermis after UV radiation exposure, and preferential adhesion of neutrophils to the irradiated epidermis was demonstrated.2

Nearly all patients with PV present with lesions in the mucous membranes of the oral cavity. Intact bullae are rarely found in the mouth; instead, lesions there tend to be painful erosions of the gingival, buccal, or palatine surfaces that heal slowly. Other mucous membranes may be involved, such as the conjunctivae, esophagus, genitals, nasal mucosa, or anus. Skin manifestations most commonly present as intact bullae with clear fluid. They rupture easily and form painful erosions. Nail involvement also is possible in the form of paronychia, subungual hematomas, or dystrophic nails. Bullae that present in skin folds can form vegetating granulomas.3

Histopathology findings in cases of PV show an intradermal blister with intracellular edema and loss of intercellular attachments. Direct immunofluorescence test results display in vivo deposits of antibodies.4 Indirect immunofluorescence testing will demonstrate intracellular antibodies, as well.5

Oral corticosteroids are the mainstay of treatment to reduce the inflammatory state by inhibiting cytokines. Immunosuppressants should also be considered for long-term management to reduce the many adverse effects of corticosteroid treatment (eg, osteoporosis, hypertension, cushingoid symptoms, hypokalemia, insomnia, emotional instability, etc). Other possible agents fort the treatment of PV include cyclophosphamide, azathioprine, mycophenolate mofetil, intravenous immunoglobulin, and rituximab.6


Pemphigus Vulgaris


Outcome of the case. The patient declined treatment with oral corticosteroids, citing a previous negative experience in which an improper corticosteroid taper had caused a rebound flare-up of her PV. She was treated with aloe vera to relieve the sunburn and was cautioned to avoid sun exposure and to use sunscreen, including on her lips. Her blisters eventually resolved without further sequelae. 


  1. Pemphigus. In: Habif TP. Clinical Dermatology: A Color Guide to Diagnosis and Therapy. 5th ed. Philadelphia, PA: Mosby Elsevier; 2010:647-655.
  2. Kano Y, Shimosegawa M, Mizukawa Y, Shiohara T. Pemphigus foliaceus induced by exposure to sunlight: report of a case and analysis of photochallenge-induced lesions. Dermatology. 2000;201(2):132-138.
  3. Svecova D. Pemphigus vulgaris: a clinical study of 44 cases over a 20-year period. Int J Dermatol. 2015;54(10):1138-1144.
  4. Helander SD, Rogers RS III. The sensitivity and specificity of direct immunofluorescence testing in disorders of mucous membranes. J Am Acad Dermatol. 1994;30(1):65-75.
  5. Judd KP, Lever WF. Correlation of antibodies in skin and serum with disease severity in pemphigus. Arch Dermatol. 1979;115(4):428-432.
  6. Cholera M, Chainani-Wu N. Management of pemphigus vulgaris. Adv Ther. 2016;33(6):910-958.



Erythema Ab Igne


Mehrdad Mac Farid, MD, RVT, and Carla Ortega, MD
Cleveland Clinic Florida, Weston, Florida

Consultant. 2018;58(2):74-75. 


A 48-year-old African American woman presented for evaluation of skin discoloration on her left thigh. She had a history of avascular necrosis of the left hip, for which she had undergone a total hip replacement 10 years prior. She had been experiencing chronic daily pain in her thigh requiring the use of a heating pad.

History. The patient denied a history of venous thrombosis, superficial thrombophlebitis, chronic kidney disease, or heart disease. Her past medical history was significant for varicose veins, which had been treated with sclerotherapy. Her surgical history included dilation and curettage of the uterus and a cesarean delivery. She denied having constitutional symptoms, including fever, weight loss, leg swelling, and skin nodules. She had never used tobacco, alcohol, or recreational drugs.

Physical examination. The patient was well appearing, with normal vital signs, height, and weight. Her neck was supple with no jugular vein distention. Cardiovascular examination findings included regular heart sounds, an audible S1 and S2, and no murmurs or gallop. Examination of the upper extremities showed no deformities, edema, clubbing, or discoloration. Examination of the lower extremities revealed moderate telangiectasia, normal temperature, and normal ankle pulses. Skin color, texture, and turgor of the lower extremities were normal. No lesions were present with the exception of a hyperpigmented, nonblanching, livedoid discoloration on the anterior aspect of the left thigh.

Based on her history and presentation, the patient received a clinical diagnosis of erythema ab igne.


Erythema Ab Igne


Discussion. Erythema ab igne is a benign dermatosis caused by direct and chronic exposure to heat. It is commonly seen in cases of exposure to the infrared radiation produced by various heat sources such as heating blankets or heat pads used to relieve chronic pain.1 Cases of erythema ab igne have more recently been reported among laptop computer users and persons exposed to heated car seats.1

Its presentation can range from asymptomatic to the presence of burning and pruritus. The heat-induced damage appears to be cumulative, months to years of heat exposure provoking alterations in the skin. The pathogenesis remains unknown; however, epidermal damage to superficial blood vessels resulting in vascular dilation and hemosiderin deposition in a reticular distribution has been suggested as a mechanism in cases associated with long-term exposure to heat.

Erythema ab igne is a clinical diagnosis based on a patient’s history of exposure to a heat source. The diagnosis can be challenging and can result in unnecessary and costly workups, including vascular imaging and blood tests for markers of connective tissue disease and vasculitis.2 Skin biopsy may demonstrate a wide range of nonspecific findings and is only useful to exclude other differential diagnoses when the presentation is not clear.3 The differential diagnosis of erythema ab igne includes livedo reticularis, which may occur in a variety of physiologic and pathologic states such as arterial occlusive disease, vasospastic and autoimmune diseases, hypercoagulopathies, endocrinopathies, infections, and drug reactions.3,4

The prognosis is generally good.3 Treatment centers on avoidance of heat exposure, which resolves skin changes in a matter of months; rarely, however, patients with a longer duration of exposure may develop permanent hyperpigmentation and atrophy of the skin.

Outcome of the case. The patient’s symptoms resolved in a matter of months with the use of nonsteroidal anti-inflammatory drugs and the avoidance of heat exposure. 



  1. Beleznay K, Humphrey S, Au S. Erythema ab igne. CMAJ. 2010;182(5):E228.
  2. Butler ML. Erythema ab igne, a sign of pancreatic disease. Am J Gastroenterol. 1977;67(1):77-79.
  3. Milchak M, Smucker J, Chung CG, Seiverling EV. Erythema ab igne due to heating pad use: a case report and review of clinical presentation, prevention, and complications. Case Rep Med. 2016;2016:1862480.
  4. Sajjan VV, Lunge S, Swamy MB, Pandit AM. Livedo reticularis: a review of the literature. Indian Dermatol Online J. 2015;6(5):315-321.


NEXT: Eruptive Xanthomas as a Manifestation of Hypertriglyceridemia

Eruptive Xanthomas as a Manifestation of Hypertriglyceridemia


Gregory Delost, DO
University Hospitals Cleveland Medical Center, Cleveland, Ohio

Taylor Edwards, OMS-IV
Ohio University Heritage College of Osteopathic Medicine, Athens, Ohio


Consultant. 2018;58(2):75-76. 


A 61-year-old African American man presented to a dermatology clinic with a rapid onset of several dozen mild pruritic lesions on his neck, forearms, sacral region, and buttocks. He had a longstanding history of similar lesions isolated to his posterior scalp with a presumed diagnosis of pseudofolliculitis barbae; these lesions had been well-controlled with intralesional triamcinolone injections.

He denied the initiation of any new medications. His medical history included poorly controlled type 2 diabetes mellitus, osteoarthritis, chronic obstructive pulmonary disease, obstructive sleep apnea, and gastroesophageal reflux disease. He also had a history of hepatitis C virus infection, for which he had undergone treatment 8 years prior.

Physical examination. Dome-shaped, yellow-orange, firm papules were present on the patient’s posterior neck, the extensor surface of the forearms, the sacral region, and the buttocks (Figures 1-3).


Eruptive Xanthomas

Eruptive Xanthomas

Eruptive Xanthomas


Diagnostic tests. Results of a punch biopsy of a lesion on the left superior sacral region revealed macrophages with abundant foamy cytoplasm within the superficial dermis (Figure 4). Results of a lipid panel revealed an elevated serum triglyceride level of 3750 mg/dL. Additional lipid panel results included a total cholesterol level of 208 mg/dL, a low-density lipoprotein (LDL) cholesterol level of 59 mg/dL, and a high-density lipoprotein (HDL) cholesterol level of 18 mg/dL. A review of his medical record showed that his hemoglobin A1c level had been consistently above 10% for the past year, with levels as high as 16.6%.


Eruptive Xanthomas

Figure 4: Dermatopathology slide of a biopsy sample showing macrophages with abundant foamy cytoplasm within the superficial dermis (×40 magnification).


Based on the patient’s clinical presentation and diagnostic test results, he received a diagnosis of eruptive xanthomas as a manifestation of hypertriglyceridemia.

Discussion. Eruptive xanthomas are a result of the deposition of lipids in the skin as a consequence of chylomicronemia and severe hypertriglyceridemia, which is causally associated with triglyceride levels above 990 mg/dL.1 Eruptive xanthomas are classically characterized as pruritic or tender clusters of small, orange-yellow papules with definite redness.2 Lesions generally range in size from 1 to 5 mm, with the buttocks and extensor surface of the extremities being the most common locations.2 The onset is typically rapid, and all lesions are classically in the same stage of development. They most commonly present in adulthood with an estimated prevalence of 1% to 4%.1

Hypertriglyceridemia may result from primary or secondary causes. Causative hereditary conditions include lipoprotein lipase deficiency and familial hyperlipoproteinemia. Secondary causes include diabetes mellitus, excessive alcohol intake, and medications such as systemic retinoids and estrogens. Occasionally, eruptive xanthomas are the presenting sign of diabetes.3 The most likely cause of this patient’s hypertriglyceridemia was uncontrolled diabetes. Pancreatitis is a potential sequela, especially when the triglyceride level is 1500 mg/dL or greater. Furthermore, individuals with eruptive xanthomas are at risk for the development of atherosclerotic disease.4

A fasting lipid panel assessing levels of cholesterol, triglycerides, very-low-density lipoprotein, LDL, and HDL should be performed in all patients suspected of having eruptive xanthomas.1 Resulting hyperlipidemia warrants further evaluation to identify the underlying cause. Patients with a presentation consistent with eruptive xanthomas often have secondary hyperlipidemia associated with diabetes, thyroid dysfunction, liver disease, or renal disease.5 If a probable cause is not identified, an inherited dyslipidemia should be considered. Skin biopsy will show intradermal macrophages with abundant foamy cytoplasm.6 The differential diagnosis should include granuloma annulare, folliculitis, pityrosporum folliculitis, steroid acne, histiocytosis, leukemia cutis, and exanthematous drug eruption.

Treatment includes lifestyle modifications such as increased exercise and dietary restriction, as well as statin therapy to control hyperlipidemia.5 Fibrates and niacin have been shown to be effective in lowering triglycerides; ω-3 fatty acids also have been shown to decrease serum triglyceride levels by increasing catabolism.7 Early diagnosis and thorough monitoring of hypertriglyceridemia can prevent more severe sequelae later in life.1,5 Skin lesions typically improve or resolve within 6 months of appropriate treatment. 



  1. Zak A, Zeman M, Slaby A, Vecka M. Xanthomas: clinical and pathophysiological relations. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub. 2014;158(2):181-188.
  2. Xanthomas and dysliproteinemia. In: Habif TP. Clinical Dermatology: A Color Guide to Diagnosis and Therapy. 5th ed. Philadelphia, PA: Mosby Elsevier; 2010:980-983.
  3. Ravić-Nikolić A, Mladenović V, Mitrović S, et al. Generalized eruptive xanthomas associated with diabetic dyslipidemia. Eur J Dermatol. 2014;24(3):394-395.
  4. Bounouar M, Mernissi F. Eruptive xanthomas announcing severe acute pancreatitis [in French]. Pan Afr Med J. 2014;17:225.
  5. Brunzell JD. Hypertriglyceridemia. N Engl J Med. 2007;357(10):1009-1017.
  6. Cooper PH. Eruptive xanthoma: a microscopic simulant of granuloma annulare. J Cutan Pathol. 1986;13(3):207-215.
  7. Rader DJ, Hobbs HH. Disorders of lipoprotein metabolism. Longo DL, Fauci AS, Kasper DL, Hauser SL, Jameson JL, Loscalzo J, eds. Harrison’s Principles of Internal Medicine. Vol 1. 18th ed. New York, NY: McGraw-Hill; 2012:​3145-3161.