Clinico-epidemiological study of lichen urticatus

Lata Sharma, LS Solanki

 Department of Dermatology and Venereology, Institute of Medical Sciences, Banaras Hindu University, Varanasi - 221005, India

Correspondence Address:
Lata Sharma
Department of Dermatology and Venereology, Institute of Medical Sciences, Banaras Hindu University, Varanasi - 221005
India

Sir,

Lichen urticatus is considered to be a hypersensitivity reaction to bites of insects, where injection of foreign protein by insect bite on skin causes IgE-mediated reaction consisting of wheals in predisposed individuals. ^[1] Asians are said to be more predisposed to intense reaction according to Stibich. ^[2] Hence it was studied.

Lichen urticatus cases attending skin and venereal disease (VD) outpatients were selected for 16 months (From February 2006 to June 2007) at University Hospital, Varanasi, a tertiary care hospital providing comprehensive medical care to the neighboring states and Nepal.

Out of 36 965 total cases, 144 were lichen urticatus, including 83 males and 61 females, the ratio was 1.36 : 1. All were Hindus except four of Muslim religion. Age was 6 months to 20 years (6.20 ± 4.90). There were 74.3, 18, 6.3 and 1.4% cases in the age groups of 0 to 5, 6 to 10, 11 to 15 and 16 to 20 years, respectively. Duration of lichen urticatus varied from 3 days to 13 years but in 62.5% of cases it was> 6 months. Percentage of cases in June, July and November were 16, 11.1 and 9.72, respectively, though cases presented through out the year.

Itching was mild in 17, moderate in 81 and severe in 52. It was more during day in 16.7% and in night in 54.9%, intermittent in 59.9% or continuous with bouts of itching in 41%. Site of initial lesions was legs in 71, face 15, hands 8 and not known in others.

In 61%, it was recurrent, where 56 cases presented in first episode, 32 in second and 56 in third or more episodes. Insect bite was considered as a cause by 67 and heat with humidity by 4 patients. Most of the patients used some topical medication. Lesions healed leaving light or dark spots or occasional scar in 1 to 2 months. Family history of similar disease was present in seven cases and allergic rhinitis with asthma in two cases. History of worms in stools was in 4.16% of patients. Majority of cases were vegetarian.

Pallor was observed in 49, inguinal lymph nodes in 14 and both in 40 patients. Nutrition was considered normal or malnutrition of grade I, II or III when the percentage was> 80, 71 to 80, 61 to 70 or 51 to 60 of their expected weight, respectively and it was found in 104, 23, 15 and 2 cases, respectively.

Lesions were found on face, arms, forearms, hands, legs and feet, on extensor surfaces bilaterally along with buttocks in 26.3%, periumbilical area, palms/soles and scalp in 26.3%, 3.4%, 2.7% and 0.7% of patients, respectively.

Hemoglobin was low in 20 cases; however, it was not related to the duration of the disease. Total leukocyte count (TLC) was high in four cases with purulent discharge from lesions in one case. In 29 cases, erythrocyte sedimentation rate (ESR) was high and was 3-4 times than the normal, but was not related to the duration. Serum protein and albumin to globulin ratio was normal in all patients. In stool, ova of Ascaris lumbricoides was in two cases, Hymenolepis nana in 1, cysts of Entamoeba histolytica in 1 and Giardia intestinalis in 1 case.

Lichen urticatus presents throughout the year, but more in summer and rainy season when insect population is more in localities where they remain undisturbed. Around Varanasi, the climate is subtropical and summer temperature varies from 32 to 46΀C. Water logging, garbage collection and unhygienic conditions, low socioeconomic strata, overcrowding, cultural habits, use of light clothing, sleeping in open at night in areas with scarcity of electricity and summer and rainy season play an important role in exposing individuals to arthropod bites.

Majority of cases were up to the age of 10 years as tolerance develops by this age. ^[2] Cases up to the age of 5 years were 51.4%, as arms and legs remain exposed in children most of the time. Lesions were also seen on scalp, periumbilical area and buttocks. Scalp is shaved due to weather conditions and also as tradition of ′Mundan Sanskar′. The infants and children are likely to be exposed below the waist line till they achieve bowel and bladder control. Nocturnal itching disturbed the night sleep in 54.9% of cases. Rook stated that general health of children can be affected in lichen urticatus, ^[3] hence general health of the patients was assessed. Malnutrition was noted in 27.8% of cases, though more than half of the children from various parts of Uttar Pradesh were found to be underweight by Vir. ^[4] Serum protein, albumin and globulin ratio were normal in all of the cases. Erythrocyte sedimentation rate was increased in 29 out of 40 cases, which is said to be less helpful in countries where chronic infections are common. ^[5]

The clinico-epidemiological features of the disease suggest that it can be prevented by keeping extremities covered, using mosquito nets, insect repellent, improving environmental sanitation, etc.

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