What is atopy? Sidestepping semantics

In vivo confocal microscopy evaluation of meibomian gland dysfunction in atopic-keratoconjunctivitis patients

PURPOSE

To clarify meibomian gland (MG) alterations in atopic keratoconjunctivitis (AKC) patients and compare the findings with obstructive MG dysfunction (MGD) patients and control subjects using in vivo confocal microscopy (CM).

DESIGN

Prospective, controlled, single-center study.

PARTICIPANTS

Twelve AKC patients (10 males, 2 females; mean age, 31.0±16.5 years), 12 obstructive MGD patients (7 males, 5 females; mean age, 37.6±5.6 years), and 26 control subjects (13 males, 13 females; mean age, 32.9±5.7 years) were recruited. No significant age or gender differences were observed between the 3 groups.

METHODS

All subjects underwent assessment of tear evaporation rate from the ocular surface (TEROS), slit-lamp examinations, tear break-up time (BUT) measurements, vital staining, Schirmer test I, meibography, MG expressibility, and CM examination of the MG (HRTII-RCM). Statistical analysis was performed using the Mann-Whitney test.

MAIN OUTCOME MEASURES

The MG acinar unit density, inflammatory cell density, MG acinar unit longest diameter, MG acinar unit shortest diameter, and MG acinar unit area as observed by in vivo CM, MG drop-out, MG expressibility grading, tear stability, tear evaporation, and vital staining scores.

RESULTS

The TEROS values, mean BUT, vital staining scores, MG expressibility, and MG dropout grades were significantly worse in AKC patients compared with those in obstructive MGD patients and controls (P<0.05). The mean values of the CM parameters in AKC patients were significantly worse than those observed in the obstructive MGD patients and controls (P<0.001).

CONCLUSIONS

Changes in MG in AKC patients seem to be more severe than in patients with obstructive MGD and controls. In vivo CM is a noninvasive, efficient tool in the assessment of MG status and ocular surface disease in AKC.

Impression cytology in atopic dermatitis

PURPOSE

This study aimed to describe the ocular surface disorder in patients with atopic dermatitis (AD).

DESIGN

A prospective case-controlled study.

PARTICIPANTS

A total of 44 patients with active AD seen at Kobe University School of Medicine, Department of Ophthalmology, during 1994 through 1996 and 22 normal control subjects were studied.

INTERVENTION

The subjects underwent routine ophthalmic examinations, tear film break-up time (BUT), Schirmer test, and conjunctival impression cytology.

MAIN OUTCOME MEASURES

Patients and control subjects were compared for tear function parameters, goblet cell density, and conjunctival squamous metaplasia grade. The relation of duration and recurrences of AD to the ocular surface disorder also was looked for.

RESULTS

The duration of atopic disease ranged from 18 to 32 years (mean, 22.8 years). The average for exacerbations was 4.5 times. Chronic allergic conjunctivitis with superficial punctate keratitis was the most frequent clinical presentation. The BUT and Schirmer test values were significantly lower in patients with AD compared with those of the control subjects. Impression cytology showed goblet cell loss and conjunctival squamous metaplasia, both of which related to the number of recurrences of AD rather than the duration of disease. Facial atopy and allergic keratoconjunctivitis (AKC) related to the metaplasia of the ocular surface (P < 0.001). Patients with reduced goblet cell density also showed low BUT levels (P < 0.001).

CONCLUSION

Ocular surface disorder of AD characterized by goblet cell loss and conjunctival squamous metaplasia seemed to evolve independently of the duration of disease but worsen with increased number of flare-ups. Direct epithelial damage by the allergic reaction, disorder of tear quality, and quantity may be important in the genesis of the atopic ocular surface disease.

Conjunctival epithelial cell hypermitosis and goblet cell hyperplasia in atopic keratoconjunctivitis

Atopic diseases that include eczema (atopic dermatitis), asthma, and seasonal and perennial rhinoconjunctivitis are common manifestations of abnormal immediate hypersensitivity. Ocular involvement, such as atopic keratoconjunctivitis, characteristically includes conjunctival and corneal inflammation, and in a severe form, conjunctival scarring, symblepharon, corneal epitheliopathy, and visual loss. To examine the conjunctival cellular abnormalities in atopic keratoconjunctivitis, we studied the in vivo differentiation and tissue-culture growth characteristics of conjunctiva from normal subjects and patients with severe atopic keratoconjunctivitis. We examined conjunctival biopsy specimens to determine epithelial mitotic rate and goblet cell frequency, and we studied conjunctival explants to determine the latent period for fibroblast outgrowth and fibroblast doubling time. The mitotic rate for atopic keratoconjunctivitis, 6.7% +/- 2.1% (11 patients), was statistically significantly greater than for normal subjects, 2.0% +/- 0.63% (seven subjects) (P = .05). Also the goblet cell frequency for atopic keratoconjunctivitis, 14.6% +/- 3.4% (11 patients), was statistically significantly greater than for normal subjects, 4.8% +/- 0.92% (seven subjects) (P = .02). The latent period for fibroblast outgrowth and the fibroblast doubling time for atopic keratoconjunctivitis were not statistically significantly different from normal control subjects. Therefore, atopic keratoconjunctivitis was associated with conjunctival epithelial hypermitosis, goblet cell hyperplasia, and normal fibroblast tissue-culture growth. These characteristics may be useful in the diagnosis of atopic keratoconjunctivitis. We previously studied another disease characterized by chronic conjunctival inflammation and scarring, cicatricial pemphigoid, which also demonstrated conjunctival epithelial hypermitosis, but in contrast there was near absence of goblet cells, and the fibroblasts were hyperproliferative. These differences may be used to distinguish atopic keratoconjunctivitis from cicatricial pemphigoid.

Nasal histamine challenge: a method to predict the efficiency of antihistamine treatment

Nasal histamine challenge (NHC) was performed on patients suffering from chronic rhinitis. The histamine was administered to the nose in the form of a spray. One hundred sixty-eight patients and 20 healthy subjects were examined. The histamine was sprayed into the nose in seven metered doses, from 0.03 mg to 3 mg. The nose was examined before and 4 minutes after each challenge. A positive reaction to challenge was indicated when the conchae swelled to the point that they impinged against the septum. We found that some patients reacted to a low dose of histamine (0.03 mg to 0.15 mg) while our control group and some other patients reacted positively only to higher doses of histamine (3 mg or more). After the first tests, NHC patients were randomly divided into two groups. One group was treated with placebo and the other group with antihistamines. Three weeks later another NHC was performed (now under treatment) and revealed that patients reacting to low doses of histamine improved significantly with antihistamine treatment, while those reacting to a high dose did not respond to antihistamines. We found the NHC to be a simple test with no complications, and one that is easily tolerated by patients, including children. Nasal histamine challenge helps to identify which patients will improve with antihistamine treatment and aids the evaluation of its efficacy.