Pruritus, papules, and perspiration.

BACKGROUND: The development of pruritus and papules with increased body temperature is a common clinical scenario seen in allergy practice, often leading to a diagnosis of cholinergic urticaria. OBJECTIVE: To describe an unusual case of miliaria and its significance in the evaluation of patients with pruritic papular eruptions that occur with increased body temperature. METHODS: An 18-year-old woman was referred to a local allergist for the evaluation of cholinergic urticaria. For the preceding 6 months, she had experienced a facial burning sensation along with diffuse pruritus accompanied by water-filled pinpoint bumps on her abdomen and extremities during exercise and with hot tub use. The lesions appeared anytime she exercised, and she reduced her workouts because of the associated discomfort. An exercise challenge was performed given the atypical description of her cutaneous symptoms. RESULTS: After indoor aerobic exercise on a treadmill, physical examination revealed facial flushing and numerous pinpoint translucent vesicles covering her abdomen. The diagnosis of miliaria crystallina was made. Given the intense pruritus she experienced with the lesions, she was prescribed cetirizine, 10 mg once daily. However, she noted no improvement with her exercise-induced miliaria. At follow-up 1 year later, her miliaria symptoms had spontaneously resolved with no sequelae observed. CONCLUSION: Intermittent, pruritic, papular eruptions that occur with perspiration can provide a diagnostic challenge when not present on initial examination. Although this presentation often leads to a diagnosis of cholinergic urticaria, our case illustrates that other disorders must be considered in the differential diagnosis. In these situations, exercise challenge is a valuable adjunct.

Miliaria rubra / Miliaria rubra

La miliaria es una erupción que afecta predominantemente a los neonatos y a la primera infancia, se produce por obstrucción del poro sudoríparo y, en su aparición, intervienen factores como exceso de sudación infecciones superficiales y aplicación de cremas. Dependiendo de la profundidad de la obstrucción, la miliaria puede ser cristalina, que es la más superficial, rubra que es la intermedia, y profunda. Las lesiones varían de vésiculas transparentes a papulovesículas o a pápulas edematosas. No se acompaña casi de síntomas y evoluciona favorablemente; desaparece en pocos días cuando cesa, el estímulo causal (AU)

Neoprene splinting: dermatological issues.

Occupational therapists are expanding their use of custom and commercial soft splints fabricated from neoprene (polychloroprene), but little has been written regarding dermatological issues associated with this material. Skin contact with neoprene poses two dermatological risks: allergic contact dermatitis (ACD) and miliaria rubra (i.e., prickly heat). Allergic reaction to neoprene is generally ascribed to the accelerants used to manufacture the man-made rubber, specifically thiourea compounds and mercaptobenzothiazole (MBT). Symptoms of neoprene-related ACD include itching, skin eruptions, swelling, and hemorrhages into the skin. Miliaria rubra creates small, red, elevated, inflammatory papules and a tingling, burning sensation. Although neoprene hypersensitivity is rare, its incidence may grow as neoprene becomes a more commonly used material. It is recommended that therapists screen patients for a history of dermatological reactions to neoprene or other materials containing thiourea compounds or MBT and educate patients to discontinue splint use if dermatological symptoms develop. Therapists are also encouraged to notify splint manufacturers regarding all ACD reactions.

Nonneoplastic disorders of the eccrine glands.

Eccrine glands are uniquely susceptible to a variety of pathologic processes. Alteration in the rate of sweat secretion manifests as hypohidrosis and hyperhidrosis. Obstruction of the eccrine duct leads to miliaria. The excretion of drugs into eccrine sweat may be a contributory factor in neutrophilic eccrine hidradenitis (NEH), syringosquamous metaplasia (SSM), coma bulla, and erythema multiforme (EM). Alterations in the electrolyte composition of eccrine sweat can be observed in several systemic diseases, most notably cystic fibrosis. This article summarizes current knowledge of eccrine gland pathophysiology.

The role of extracellular polysaccharide substance produced by Staphylococcus epidermidis in miliaria.

BACKGROUND: Previous studies have indicated that cutaneous bacteria, particularly coagulase-negative staphylococci, play a role in the pathogenesis of miliaria. An accumulation of periodic acid-Schiff (PAS)-positive material has been described as blocking the sweat duct in miliaria. Furthermore, a PAS-positive extracellular polysaccharide substance (EPS) has been identified as a product of some strains of Staphylococcus epidermidis. OBJECTIVE: We evaluated the relative ability of various species of coagulase-negative staphylococci to induce miliaria with particular reference to the potential role of EPS. METHODS: We inoculated various strains of coagulase-negative staphylococci on the volar forearms of subjects under an occlusive dressing coupled with thermal stimulation. Ability to induce miliaria as well as microbiologic, histologic, and immunostaining features were evaluated. RESULTS: Miliaria was induced only with strains of S. epidermidis; other species including S. haemolyticus, S. hominis, S. cohnii, S. saprophyticus, and S. simulans were not capable of inducing miliaria. Moreover, only S. epidermidis strains capable of producing EPS were capable of inducing miliaria. CONCLUSION: Our data indicate that EPS is the PAS-positive material that obstructs the delivery of sweat to the skin surface in miliaria and therefore demonstrate that the EPS produced by S. epidermidis plays a central role in the pathogenesis of miliaria. Furthermore, in a survey of staphylococcal flora isolated from 68 subjects, EPS-producing strains were found to be common.

Persistence of impaired heat tolerance from artificially induced miliaria rubra.

Ten volunteers were heat acclimatized to 48.9 degrees C (Ta), 20% rh for 7 days to complete a 100-min walk on a level treadmill (1.56 m x s-1). Subjects were then divided into experimental (n = 6) and control (n = 4) groups. Miliaria rubra (heat rash) was then induced on the experimental subjects by wrapping them for 3 days in polyethylene plastic. All six developed marked miliaria with involvement of 40-70% of the total body surface area. All subjects were reexposed to walking in the heat on the 7th day after unwrapping, by which time rash was clinically indetectable, and again 14 days after unwrapping. On the first test (day 7) only one of the rashed group, and on the second test (day 14) only two could complete the 100-min walk; the control group finished without difficulty on both days. Body heat storage for the rash group was 2.5 times that of the control group on day 7 and 1.5 as great on day 14; measurements of mean body temperature (Tb) on the rash group indicated a much greater heat stress when compared to their own prerash-acclimatized values or those of the control group. These data demonstrate the potential of "healed" miliaria in the etiology of clinical heat illness.

Heat intolerance as a function of percent of body surface involved with miliaria rubra.

Twenty-four heat-acclimatized male volunteers were wrapped as previously described (Am. J. Physiol. 239 (Regulatory Integrative Comp. Physiol. 8): R226-R232, 1980) but to produce miliaria rubra (heat rash) in specific regions of the body. Three experimental rash groups were involved: 1) the torso (17% total skin surface rashed, n = 6), 2) torso and arms (38%, n = 8), or 3) legs (41%, n = 6), while four subjects served as controls. All subjects were reexposed to walking in the heat on the 7th day after unwrapping, and again 14, 21, and 28 days after unwrapping. When compared to responses for the last heat acclimatization day, tolerance time and sweat rate were lower and mean body temperature and delta heat storage significantly higher for experimental rash subjects contrasted to the controls for up to 21 days; however, no significant differences between the three rashed groups were found. The critical amount of surface area for heat intolerance from heat rash appears to be related to the specific region of the body and associated sweating responses; smaller rashed areas of the trunk, because they have greater potential for abundant sweating, may produce similar responses to heat stress as larger rashed areas of the limbs. Heat intolerance due to rash was not resolved until after 21 days.