Infectious disease update.

Many newly described or "re-emerging" infectious diseases may present to the dermatologist, often with potentially life-threatening implications. Prompt recognition and early intervention can greatly diminish the morbidity and mortality associated with these diseases.

Pseudoporphyria.

Pseudoporphyria is the term used to describe a photodistributed bullous disorder with clinical and histologic features of porphyria cutanea tarda, but without accompanying biochemical porphyrin abnormalities. Medications, chronic renal failure/dialysis, excessive sun exposure and UVA radiation have all been reported to cause pseudoporphyria. Recognition, diagnosis, and appropriate management of pseudoporphyria are discussed.

Xerosis in hypothyroidism: a potential role for the use of topical thyroid hormone in euthyroid patients.

Xerosis is an extraordinarily common problem in dermatology. Despite the knowledge of well recognized aggravating factors, its etiology is an enigma, and the management of the condition is often suboptimal. Dry skin may be a manifestation of hypothyroidism. The nature of this association is reviewed, culminating in the speculation that topical thyroid hormone may represent a useful modality in euthyroid patients with xerosis or other disorders of keratinization.

Protease inhibitor-induced lipodystrophy.

The development of lipodystrophy as evidenced by central obesity, "moon facies," and a "buffalo hump" is a classical feature of Cushing's disease. Recently an association of "lipodystrophy" with the use of protease inhibitors has been reported. We describe a patient with lipodystrophy secondary to protease inhibitor therapy for HIV infection.

Toxin-mediated streptococcal and staphylococcal disease.

After several decades of seemingly decreasing virulence, streptococcal and staphylococcal infections have reemerged as a major source of morbidity and mortality. Within the past 2 decades, not only have well-established diseases such as rheumatic fever begun to reappear. but also many new entities, such as toxic shock syndrome, streptococcal toxic shock syndrome, recurrent toxin-mediated perineal erythema, and recalcitrant erythematous desquamating disorder have been described. Central to the renewed importance of these bacteria has been the production of circulating toxins, which often function as superantigens in causing the clinical manifestations, morbidity and mortality associated with these diseases.

Urticaria pigmentosa presenting with massive peripheral eosinophilia.

A 5-month-old Hispanic boy had a diffuse eruption and massive peripheral eosinophilia. Mastocytosis was diagnosed by skin biopsy and Giemsa stain. Other causes of eosinophilia were ruled out by bone marrow examination and negative cultures. The patient's course improved with antihistamines and the removal of mast cell degranulating agents. Clinicians need to be aware that mastocytosis should be considered in the differential diagnosis of eosinophilia.

Recurrent toxin-mediated perineal erythema.

BACKGROUND: Important new diseases due to bacterial toxins functioning as superantigens have been described with increasing frequency within recent years. Toxic shock syndrome, recalcitrant erythematous desquamating disorder, streptococcal toxic shock-like syndrome, and, most recently, mucocutaneous lymph node syndrome (Kawasaki disease) have been etiologically linked with certain staphylococcal and streptococcal toxins. We describe two patients with a novel clinical presentation of toxin-mediated disease, which shares certain clinical features with mucocutaneous lymph node syndrome. OBSERVATIONS: Two otherwise healthy young male adults developed recurrent erysipelaslike perineal erythema, which regularly erupted within 1 to 2 days of the onset of acute pharyngitis. Accompanying signs included mucosal changes and acral erythema with desquamation. Throat cultures obtained during the acute episodes yielded toxin-producing Staphylococcus aureus from one patient and toxin-producing Streptococcus pyogenes from the other. CONCLUSION: The recurrent nature, age predilection, and clinical presentation suggest that our patients display a unique clinical syndrome due to toxin-producing bacteria.

Thalidomide-resistant HIV-associated aphthae successfully treated with granulocyte colony-stimulating factor.

Thalidomide has been advocated as the treatment of choice for recalcitrant aphthae. We describe the case of patient with HIV infection and extensive aphthae whose condition failed to respond to corticosteroids, cyclosporine, and thalidomide. The patient's course was complicated by colonic aphthae. Rapid and sustained resolution was achieved through treatment with granulocyte colony-stimulating factor, a previously unreported therapeutic option.

Serious and life-threatening drug eruptions.

Drug eruptions are common iatrogenic diseases. Although most of these conditions are benign and self-limited when use of the responsible drug is discontinued, several subtypes of drug eruptions are characterized by significant morbidity and mortality. The more dangerous types include erythroderma, leukocytoclastic vasculitis, anticonvulsant hypersensitivity syndrome, Stevens-Johnson syndrome and toxic epidermal necrolysis. Relatively few medications are repeatedly implicated in the pathogenesis of severe reactions. Prompt recognition of drug eruptions and early intervention are necessary to prevent the serious consequences of this group of iatrogenic diseases.

Acute generalized exanthemic pustulosis.

Acute generalized exanthemic pustulosis often presents dramatically with the abrupt onset of a widespread pustular eruption on an erythematous base, with a frequently positive Nikolsky sign. In most cases, penicillins or macrolides are causally related. The main differential diagnosis of a generalized pustular eruption in a febrile patient is pustular psoriasis, which can be differentiated on both a clinical and histologic basis.

Perioral dermatitis in childhood.

BACKGROUND: Although perioral dermatitis has been well described in young women, little has been reported about this condition in children. OBJECTIVE: The purpose of this study was to define more clearly the features of perioral dermatitis in childhood. METHODS: Fourteen children with perioral dermatitis were assessed for clinical features, therapeutic response, and possible etiologic factors. RESULTS: Fourteen cases of perioral dermatitis were seen in 16 months, far exceeding the expected prevalence in childhood. Although the childhood variant shares many characteristics with the adult form, children often have periocular and perinasal lesions, as well as a higher relative incidence in boys. Mid- to high-potency topical corticosteroids were used in seven of the patients (50%) and likely contributed to the pathogenesis. All children responded rapidly to treatment. CONCLUSION: Perioral dermatitis in childhood, often iatrogenic, is more common than previously reported.