Naeem Raza  ( Department of Dermatology, Combined Military Hospital, Kharian, Pakistan )
Syed Nurul Rasool Qadir  ( Department of Dermatology, Combined Military Hospital, Kharian, Pakistan )
Amer Ejaz  ( Department of Dermatology, Combined Military Hospital, Kharian, Pakistan )

Erythema ab igne is a localized red brown reticular pigmentation, resulting from chronic, repetitive exposure to sub maximal heat, insufficient to cause burn. A study was carried out at the dermatology outpatient department of Combined Military Hospital, Abbottabad during January-April 2005 with the purpose to see frequency of erythema ab igne. Fourteen patients were identified, interviewed and examined in detail. Nine were females, eight of them housewives, and five were males. Age of the patients ranged from 9 to 60 years with a mean of 36.5 + 14.8 years. Body Mass Index (BMI) of the patients ranged from 13.5 to 33.5, six of them were in the BMI range of between 25.1 and 30. Nine patients belonged to rural areas. Erythema ab igne was not associated with thyroid disease or any other systemic or psychiatric illness.

Skin is important in preserving homeostasis between man and the environment. One major role of the skin is in thermoregulation; however, from a sensory point of view, the skin thermoreceptors play a relatively minor role in

modifying core temperature and have a greater role in mediating behaviour. Prolonged exposure to moderate degrees of heat can result in erythema ab igne. It is a localized red brown reticular pigmentation which results from chronic, repetitive exposure to sub maximal heat, insufficient to cause burn.1 The histological changes in erythema ab igne are non-specific. In early lesions epidermal atrophy and melanin incontinence occurs. Collagen degeneration along with increased amount of elastic tissue may also be seen within the dermis. In later stages, focal or confluent hyperkeratosis, dyskeratosis, keratinocyte atypia and occasionally melanocyte atypia may be seen.2,3 Erythema ab igne is reversible initially, if the repeated exposure to heat is eliminated. Once the pigmentary changes appear, the eruption is long-standing.2 The association of erythema ab igne with premalignant or malignant lesions, though occasionally described, seems relatively infrequent.4 The associated premalignant and malignant conditions include actinic keratosis, Bowen's disease5, merkle cell carcinoma6 and squamous cell carcinoma.1
In developed countries, with the advent of central heating, the overall incidence of erythema ab igne is declining, although in developing countries like Pakistan, patients with erythema ab igne are still seen in each winter, particularly in cold weather areas. The purpose of this study was to see the frequency of erythema ab igne during winter season at a moderately cold weather station.